[!!!][TASK] Drop DB field sys_language.static_lang_isocode

The database field "static_lang_isocode" in the DB table
"sys_language" is configured via static_info_tables, however
due to legacy reasons, this was added in TYPO3 Core,
as some references were put there. It is now possible
to remove any references to this field, and have the third-party
extension deal with it.

Resolves: #88583
Releases: master
Change-Id: I5c366c84d21e0d291ec32d44c0b2c2e1064f669d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60887


Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>