maintain deprecated \OC::$session when getting or setting the session via the server container or UserSession

restore order os OC::$session and OC::$CLI

remove unneded initialization of dummy session

write back session when $useCustomSession is true

log warning when deprecated app is used

Fixes https://github.com/owncloud/core/issues/10624

Fix copy paste fail

Add unittest for comma separated headers

Revert 3rdparty

Previously we used uniqid() here.
However this means that the behaviour is not reproducable, so
when uploading files into a "empty" folder, the folders name is
different.

If there would be a md5() hash collition, the deduplicate check
will spot this and append an index later, so this should not be
a problem.

Fix #6722

This can now be achieved by setting `appstoreenabled` to `false` in config.php

Format file

Removing calls to deprecated classes and using internal method to get via http

Missed a character

Fix inverted logic

Fixes the issue that makes SQLite freeze on later tests.

Signed-off-by: Stephan Peijnik <speijnik@anexia-it.com>