Refer to relative path instead of absolute path

There is no need to refer to the absolute path here if we can use the relative one.

Conflicts:
	lib/private/templatelayout.php
Add unit tests for convertToRelativePath
Add "$_SERVER['REQUEST_URI']" to fix the unit tests

Let's hope that works
Hide SQLite information on setup when autoconfig is used
Add proper setup and teardown

Properly restore REQUEST_URI and SCRIPT_NAME after test runs
Merge pull request #11593 from owncloud/useRelativePathToOwnCloudInstallation

Refer to relative path instead of absolute path
Merge pull request #11666 from owncloud/setup-hidesqlitemessageforautoconfig

Hide SQLite information on setup when autoconfig is used
Warn for password reset when files_encryption is enabled

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 :dancers:

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