Use EventDispatcher to allow additional setup of auth backends - move federation auth to federation app

Unit test contact provider registration

Do not lower the sharee search

Show the well-known URL check as info instead of error

Fixes #21639

When lowering the remote search it break remotes that have uppercase
letters like foo@example.com/ownCloud/

Backends do the mathcing so they should also make sure that the search
string is converted to the format they require.

* ref https://github.com/owncloud/core/pull/21562#issuecomment-170344549

fix identation in public/irequest.php

Replace deprecated function calls to SecureRandom

Remove unused deprecated function from l10n.php

Revert "Remove unneeded check if htaccess test file already exists"

fix principal constructor for dav

Fix OAuth external storage auth for step 2

improve personal page template

remove unneeded 'goto' prefix from settings anchors

webDAV select bug fixed

Stricter autoloader

Assume apps from the appstore are compatible with the current version

Do not increase filecount in web on file update

Remove generateRandomBytes from OC_Util

remove extra slogan footer from Personal and Admin pages