* 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

Otherwise every time the AppStore was opened a lot of connections to the AppStore server were made which resulted in a terrible performance.

This changeset will cache the response for a sensible time so that only the first request will be somewhat slow.

Performance changes:
- Loading a category took previously more than 3 seconds on my machine. Now for every follow-up request it takes less than 200ms, resulting in a performance gain of 1950%
- Loading the category list took previously about 750ms - now it takes 154ms, a total performance gain of 395%

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

* supply mail address
* send mail with username and URL to that mail address
* option to temporary enable this feature

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.

Add switch to enforce SSL for subdomains

Add unit tests

Add test for boolean values

Camel-case

Fix ugly JS

Let's migrate those two new files.

- Do not store the password (fixes https://github.com/owncloud/core/issues/11385)
- Refactor to AppFramework
- Add unit tests

Conflicts:
	settings/admin/controller.php