Expose configuration types, improve configuration interface, add docs

[timvisee]

This PR does a few things, most notably:

• changes the QdrantConfig builder interface to more closely match with API type builders for example, see the removed with_ prefixes:
• move configuration types into config submodule
• expose AsTimeout, AsOptionApiKey and CompressionEncoding as users might need these while configuring
• adds extra documentation

All Submissions:

• [x] Contributions should target the dev branch. Did you create your branch from dev?
• [x] Have you followed the guidelines in our Contributing document?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

New Feature Submissions:

1. [x] Does your submission pass tests?
2. [x] Have you formatted your code locally using cargo +nightly fmt --all command prior to submission?
3. [x] Have you checked your code using cargo clippy --all --all-features command?