Allow configuring background job mode from the console

Maintenance mode message might be misleading

Disable the cache updater when doing the encryption migration

Cleanup config.sample.php

Don't swallow errors in console.php

fix files external test run and add common-tests option

Add detection for invalid CLI configuration for settings page

Shares should have a least read permission

* Throw 400 when a share is created or updated without read permissions
* Added unit tests

Show time difference of last cron run instead of absolute time

Disable some server checks when running on HHVM

Ref https://github.com/owncloud/core/issues/10837#issuecomment-76516839

This change will log all failures that prevent the CLI cronjob from happening to the database and display a warning to administrators when an error happened.

To test:

1. Configure some invalid CLI php.ini settings
2. Enable the CLI cronjob and run php cron.php
3. See the errors printed and also in the admin page
4. Configure the CLI settings correctly
5. Errors should be gone.

Fixes https://github.com/owncloud/core/issues/13994

Use custom attribute instead of the div identifier

Otherwise problems arrive when a username contains characters such as an `@`

Fixes https://github.com/owncloud/user_shibboleth/issues/38

Fix cache update when doing a rename that overwrites the target

AppFramework StreamResponse