Backport of #8183 to stable6

Some headers were currently only added to the templates but not to
other components (e.g. SabreDAV / JSON / etc...)
The migration to base.php ensures that the headers are served to all
requests passing base.php
Backport of #8197 to stable6

This extends mimetypes.list.php to be a white-list of known secure mime
types as well as offering secure alternatives for know potentially
malicious mime types.
I kept this in the OC_Helper and OC\Files\Type\Detection classes as
each backend has its own way of detecting mime types.

This supersedes #8184 as discussed in owncloud/security-tracker#56
Check whether the user has permissions to add personal storage backends

Quick’n dirty back port of #8182 - master has a better fix but that
should be good enough…

missing return - OCP\JSON::success does not terminate the PHP process - which is good ;-)

Use error instead of success

Revert "Use error instead of success"

This reverts commit e2d5535a5aa436c3896e46f0b9e8ff1bd5640d4d.

Use error instead of success
Update 3rdparty submodule
Backport of #8164

Added improved version of patch by @blizzz in https://github.com/owncloud/core/issues/6651#issuecomment-32261257 to stop filter settings from being reset under a race condition.

Moved LdapFilter into a separate js file in user_ldap.

Changed conditions in user_ldap's ldapFilter.js to use ===, fixed indentation.

fix comparison in determineMode, fixes problems with restoring the filter mode (assisted or manually) on page refresh

Give hint when composing filter failed

fixing some JSHint warnings
Merge pull request #8260 from owncloud/stable6-backport-8183-and-co

Backport of #8183 and #8197
remove OC_GROUP_BACKEND_GET_DISPLAYNAME option for group backends
LDAP: getDisplayNamesInGroup is not an option for group backends anymore
clean up group backends
remove now unnecessary test
implement getDisplayNames in group manager
adjust user manager tests
test for group manager's displayNamesInGroup
trim must not be used in empty in PHP < 5.5
keep the constant to not provoke PHP warnings
fix after rebase
Merge pull request #8261 from owncloud/stable6-backport-8182

Backport of #8182
Merge pull request #7745 from owncloud/fix_6946_stable6

Group Database backend must not gather user details itself but ask user backends, fixes #6946 in stable6
6.0.3 RC1
fix layout of external storage config table

Conflicts:
	apps/files_external/css/settings.css