Collection name under test is equal to the test module name, without `.py` suffix.
* Helps by debugging/tracing failed tests and find relevant logs lines in qdrant log files
* Opens up a possibility to run tests in parallel, given that there are no data sharing
between test modules
Change details:
* defined module scoped `collection_name` fixture in `conftest.py`
* removed `collection_name` module variable
* each test signature modified to declare the dependency to `collection_name` fixture
* `@pytest.mark.parametrize` migrated to `@pytest-cases.parametrize` in cases when
`collection_name` was used as the value
