Update adapter.php

Modified insertIfNotExist() to support NULL values
add unit test
Also update sqliteadapter
Remove special case for css in OC.filePath
improve logo flexibility to fix wide custom logo alignment, fix #9339
Libreoffice config folder needs to be set

In order to avoid conflicts between multiple instances installed on one server, it's required to define a LibreOffice configuration folder per instance.

Just like with my PR for the documents app (https://github.com/owncloud/documents/pull/353), I propose to use /tmp/owncloud-instanceid
Initialize an event source when we start using it, not in the constructor
Add event source to the public api
Use the public api to get event sources
env:UserInstallation was already there in master

My changes were made against stable7 and I merged them to the file in master, so this version is now the properly merged file for master.
I'm just adding `owncloud-<instanceid>` to the path where temp files are stored.
Use correct language package so the subject is correctly translated

Fix #10847
Fix broken new lines in plain text mail template
Explicitly cast id and validate type
Better phpdoc and method naming
Initial work on shorter links
Use a route instead of s.php and convert tokens asap
Adapt token size to new generation and add an option for free length specification

Minimum size is 3 = 46656 tokens, maximum size is 64, which is what our DB allows.
Change config.sample entry and use MediumSecurity
Use base62 and remove configuration options for link length
Readd TOKEN_LENGTH