Autogenerate sharedCacheKeyPrefix setting

This is done via a command triggered by composer update or install.

also cleaned up the entry point (e.g. remove used variable)

Bug: 70889
Add group, covers tags and more tests
Pin property suggester version to 1.1.1
Fix path for tests in UnitTestsList handler
Merge pull request #7 from wmde/settings

Autogenerate sharedCacheKeyPrefix setting