Add hook_entity_translation_access()

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Removing the tests tag as they were added in #18

Will need a change record to announce the hook.

Added patch against #18 in 10.1 version

Patch in #25 doesnt contain all the changes present in patch from #18

Changes to file core/modules/content_translation/content_translation.api.php is missing in #25

I have hidden the patch in comment #25.

Maybe we should close this one in favor of Content translation access control 📌 Content translation access control Needs work
I've succesfully used that one to be able to provide entity access conditions on create translation, update translation or delete translation.
Without the need of an additional hook.