Check coverage of existing API-tests and list them here

A lot of features are currently not tested within our test-suite. The realm of this Feature is to check the existing features and create a "wishlists" of API-tests to add that then can result in concrete Issues.

• Test PM roles: looped test, that does basic things (import 1-segment task with LR pretranslation, assign editor user, change segment with this user, export it) for PM, CLIENT PM, PMLIGHT => https://jira.translate5.net/browse/TRANSLATE-3962
• OpenAI test
• tests for all non-import task-operations (autoqa, analysis) => https://jira.translate5.net/browse/TRANSLATE-3961
• test (configurable) XLIFF import tag-processing/whitespace "specialities"
• single segment lock and unlock feature / bulk locking unlocking