Refactor \OC\Memcache\Factory

Caches divided up into two groups: distributed and local. 'Low latency' is an
alias for local caches, while the standard `create()` call tries to get
distributed caches first, then local caches.

Memcache backend is set in `config.php`, with the keys `memcache.local` and
`memcache.distributed`. If not set, `memcache.distributed` defaults to the value
of `memcache.local`.

Make sure we use Jasmine 2 for running JS unit tests

Add --show-password option to ldap:show-config

Fix PHPDoc

That apparently went lost when changing the signature.

Add unit test for selection overlay actions in trashbin

Add a test for ObjectStore\NoopScanner

adding a windows smb config for testing to ci

Avatars in share dialog fixes

Since aa821ecc leading and trailing slashes are
trimmed in the file cache paths

Update scanFile() and scanChildren() to the new signature of the parent ...

Remove unnecessary backslashes from translations

Let users configure security headers in their Webserver

* Avatar for "xxxx share with you..." to the left
* Avatars for groups and remote shares (use default placeholder)
* Modified and added unit tests
* Use the same css for all the avatars in the dropdown

Jenkins #14650

We were using the SMB and SFTP backends, which since Icewind's new SMB library
results in an actual attempted connection just by constructing the storage.
This commit replaces all references to real storages (except when necessary)
with a dummy storage class.

use `dbtableprefix` for temp table and index names

Read from IRequest instead of reading twice

Add a repair step to delete old tables

proper description of appcodechecker in config sample

[Master] Remove hacky Substring support for MSSQL

fix for loading spinner reappearing after errors in db-connection

Remove "Download from URL" feature