Add missing sqlite3 extension to require-dev as it is needed for the unit tests.

Memcache server always seen as down when using moxi

Now also considers any attributes.po in the configured theme, if any.
Makes the attributes.extradictionary config setting obsolete.

Fix entity data size for MySQL

Scrutinizer Auto-Fixes

This commit consists of patches automatically generated for this project on https://scrutinizer-ci.com

We could use it everywhere, but it's better to reduce the already big
amount of configuration options the admin is confronted with than the
small problem this option solves.