Migrate new app settings to AppFramework

Properly catch 503 storage not available in getQuotaInfo

On Windows platform we have no stable etag generation - yet

Make supported DBs configurable within config.php

This commit will make the supported DBs for installation configurable within config.php. By default the following databases are tested: "sqlite", "mysql", "pgsql". The reason behind this is that there might be instances where we want to prevent SQLite to be used by mistake.

To test this play around with the new configuration parameter "supportedDatabases".

When doing a PROPFIND on the root and one of the mount points is not
available, the returned quota attributes will now be zero.

This fix prevents the expected exception to make the whole call fail.

allow passing db driver options

Generate stable etags for local files

Fix PHPDoc

Stop my IDE and Scrutinizer from complaining.

Setting moment locale based on user selection

Add type hinting to functions

Add missing DB rollback functionality

Cleanup handling of temporary files

disable database migration unit tests for MSSQL

It's only reasonable to have proper type hinting here which might even help us to catch bugs.

Use function outside of loop

Otherwise the function is executed n times which is a lot of overhead

Make files non executable

Prevent division by zero

There is not much sense in having these files marked executable, we should avoid that.

Load avatar in header via PHP

Remove unreachable statement

Potentially fixes https://github.com/owncloud/core/issues/11742