[ticket/10744] Prevent installing styles with reserved names

PHPBB3-10744
[ticket/10744] Type hint objects for IDE usages

PHPBB3-10744
[ticket/10744] Fix some doc blocks

PHPBB3-10744
Merge pull request #3094 from nickvergessen/ticket/10744

Ticket/10744 Prevent installing styles with reserved names
Merge branch 'develop-ascraeus' into develop