EST-218: can now create property invoice number numerator once more.

In addition:
* have exposed "invoice numerator" as a contributed property on the Property entity
  * and "create invoice numberator" as a contributed action underneath
* removed the delegating calls in EstatioAdministrationService (this is where the bug was)
  because should be using the logical service action functionality (ISIS-443) - not sure why I reverted this
* refactored to exploit fix in ISIS-443 (just committed) re: grouping other services against the new "OtherServices" placeholder repo
* minor change to layout of FixedAssetRole (put 'type' first, reads better in FixedAsset#roles table)