Remove dependencies

[lu-pl]

• loguru
• hypothesis
• typeguard
• langcodes
• pytz

Actually, it would be cool if rdflib was the only dependency of lodkit!

[lu-pl]

Removing those dependencies should be done incrementally, as part of a general library review.

[lu-pl]

Another option would be to remove all superfluous dependencies all at once and also delete most of the test suite (actually everything but the recently updated lodkit.ttl tests). This would remedy the current road blocks and bypass cumbersome incremental removal of dependencies.

One question that this raises is, if such a change should constitute a dev branch that only gets merged after the planned complete library review.