Without /dev/urandom being available to read the medium RNG will rely only on the following components on a Linux system:

1. MicroTime: microtime() . memory_get_usage() as seed and then a garbage collected microtime for loop
2. MTRand: chr((mt_rand() ^ mt_rand()) % 256)
3. Rand: chr((rand() ^ rand()) % 256)
4. UniqId: Plain uniqid()

An adversary with the possibility to predict the seed used by the PHP process may thus be able to predict future tokens which is an unwanted behaviour.

One should note that this behaviour is documented in our documentation to ensure that users get aware of this even without reading our documentation this will add a post setup check to the administrative interface.

Thanks to David Black from d1b.org for bringing this again to our attention.

Also added unit-tests and better error-handling

Allows administrators to disable or enabled experimental applications as well as show the trust level.

Also used the opportunity to refactor it into an AppFramework controller so that we can unit test it.

Fixes https://github.com/owncloud/core/issues/14956

Replaces the OC_Mail and phpmailer with SwiftMail allowing us to mock it properly.

Fixes the unit test execution on master on local machines and https://github.com/owncloud/core/issues/12014

Conflicts:
	3rdparty
	lib/private/server.php
	lib/public/iservercontainer.php
	tests/lib/mail.php
	tests/settings/controller/mailsettingscontrollertest.php

Conflicts:
	3rdparty
	lib/private/mail.php
	lib/private/server.php
	lib/public/iservercontainer.php
	settings/ajax/lostpassword.php
	settings/application.php

Doing this in the PHP code is not the right approach for multiple reasons:

1. A bug in the PHP code prevents them from being added to the response.
2. They are only added when something is served via PHP and not in other cases (that makes for example the newest IE UXSS which is not yet patched by Microsoft exploitable on ownCloud)
3. Some headers such as the Strict-Transport-Security might require custom modifications by administrators. This was not possible before and lead to buggy situations.

This pull request moves those headers out of the PHP code and adds a security check to the admin settings performed via JS.

A forbidden should throw a 403 and this makes it easier for me to do some automated testing.

* reason: nice to know before password change in user management
* restore is possible:
	* encryption is disabled
	* encryption is enabled, admin and user has checked the
	  restore option
* if not possible:
	* highlight users row in red once the admin wants to change the password
	* show also a little tipsy

Previously when $gid was empty the users were not filtered at all. Rendering the search function in the user management pretty useless.

Fixes itself

add logSettingsController

add download logfile button

move getEntries to LogSettingsController

move set log level to logsettingscontroller.php

add warning if logfile is bigger than 100MB

add unit test for set log level

fix typecasting, add new line at EoF

show log and logfile download only if log_type is set to owncloud

add unit test for getFilenameForDownload

* introduced new route settings/users/{id}/mailAddress
* kept old responses
* better error messages
* dropped lostpassword.php from settings/ajax
* cleaned up the UserList.add() and hand in user object instead of
  each attribute as another parameter
* check for change permission of mail address
* proper response messages

* add switch to settings to show user backend
* user classes for headers and rows to unify the show/hide statement
* add user backend to response of user create request
* proper markup in settings area

This adds a "backend" type filter to the index REST route which is a pre-requisite for https://github.com/owncloud/core/issues/12620

For example when calling `index.php/settings/users/users?offset=0&limit=10&gid=&pattern=&backend=OC_User_Database` only users within the backend `OC_User_Database` would be shown. (requires sending a CSRF token as well)

Depends upon https://github.com/owncloud/core/pull/12711

This change will expose the user backend via the REST API which is a pre-requisite for https://github.com/owncloud/core/issues/12620.

For example:
````json
[{"name":"9707A09E-CA9A-4ABE-A66A-3F632F16C409","displayname":"Document Conversion User Account","groups":[],"subadmin":[],"quota":"default","storageLocation":"\/Users\/lreschke\/Programming\/core\/data\/9707A09E-CA9A-4ABE-A66A-3F632F16C409","lastLogin":0,"backend":"OCA\\user_ldap\\USER_LDAP"},{"name":"ED86733E-745C-4E4D-90CB-278A9737DB3C","displayname":"Hacker","groups":[],"subadmin":[],"quota":"default","storageLocation":"\/Users\/lreschke\/Programming\/core\/data\/ED86733E-745C-4E4D-90CB-278A9737DB3C","lastLogin":0,"backend":"OCA\\user_ldap\\USER_LDAP"},{"name":"71CDF45B-E125-450D-983C-D9192F36EC88","displayname":"admin","groups":[],"subadmin":[],"quota":"default","storageLocation":"\/Users\/lreschke\/Programming\/core\/data\/71CDF45B-E125-450D-983C-D9192F36EC88","lastLogin":0,"backend":"OCA\\user_ldap\\USER_LDAP"},{"name":"admin","displayname":"admin","groups":["admin"],"subadmin":[],"quota":"default","storageLocation":"\/Users\/lreschke\/Programming\/core\/data\/admin","lastLogin":"1418057287","backend":"OC_User_Database"},{"name":"test","displayname":"test","groups":[],"subadmin":[],"quota":"default","storageLocation":"\/Users\/lreschke\/Programming\/core\/data\/test","lastLogin":0,"backend":"OC_User_Database"}]
```

First step of a somewhat testable user management. - I know, the JSON returns are in an ugly format but the JS expects it that way. So let's keep it that way until we have time to fix the JS in the future.

This patch wil warn the user of the consequences when resetting the password and requires checking a checkbox (as we had in the past) to reset a password.

Furthermore I updated the code to use our new classes and added some unit tests for it 

Fixes https://github.com/owncloud/core/issues/11438

See https://github.com/owncloud/core/pull/12175#issuecomment-63054620

Add switch to enforce SSL for subdomains

Add unit tests

Add test for boolean values

Camel-case

Fix ugly JS