Use iterator() and don't allow to grow the QS cache
Editor msg: handle default opts
Editor: prevent working on obsolete units

Follow-up of #3322, which only prevent working on units from obsolete
stores, not obsolete units from non-obsolete stores.
Editor: fixed reloading
Editor: better way to display obsolete messages
Cleanup: breathe
Cleanup: removed dead code
Cleanup: store paidTaskTypes at the module level

Let's not rely on globals for templates either.
Cleanup: use module, don't rely on globals
ItemDelete: added propTypes
ItemDelete: decoupled help text from users
Admin app: decoupled data types from app init
Major cleanup to reduce diff in respect to stable