[!!!][TASK] Remove tx_ter_extensions & queue & importer task

This change is the final change to remove any database tables
from "EXT:ter", and remove any migration from TER v1 (SOAP) to
TER v2 via a scheduler task.

This change removes:
* tx_ter_extensions (versions of an extension)
* tx_ter_extensionqueue (+ its UploadQueue API object)
* ImportExtensionsFromQueueTask (all migrated to ExtensionVersion for now)

All DB rows are written directly into tx_terfe2_domain_model_version and
its related tables.

The API "ExtensionVersion->upload()" now produces everything necessary
including notifications (which can be built via PSR-14 in the future).

This also actually means that extensions are automatically available
RIGHT AWAY after uploading an extension via the GUI or the SOAP API.

Next Steps:
* Refactor our upload API to make it more resistent and moving into a Event Sourcing concept (thinning out all underlying logic from ExtensionVersion again)
* Refactor the permission concept and integrate it nicely
* Remove dependencies to the SOAP API in EXT:ter_fe2
7 jobs for feature/remove-old-db-tables in 8 minutes and 33 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Maintenance
manual Get dump for local environment #21973
allowed to fail manual
 
  Test
passed test:composer #21976

00:02:11

passed test:php #21975

00:01:43

passed test:typoscript #21974

00:00:32

passed test:unit #21977

00:03:29

 
  Build
passed build #21978

00:01:53

 
  Layout
passed layout #21979

00:03:09