MemoryLeak rejigging
Added controller for querying enumerations
Add two enum sources for querying enumerations:

  * One for the frontend, which uses its MemoryLeak module to manage caching of values

  * One for everything else, which just fetches them once
Add webhook listener for changed enumerations
Refactored the way enumerations are stored to turn enumerations into JSONModel.
Enumeration migrations
Save having to open DB connections manually by exposing $testdb to the test suite
Add permissions
WIP enumeration frontend stubs

WIP Add enumeration frontend thingies

Move the dynamic enumeration translation definitions to a dedicated locales file

Tweak enumeration forms to operate in dialogs
Fire an ENUMERATION_CHANGED webhook event when the set of enum values changes.