Cachetoolsutils

- Add `LockedCache` class for shared cache and threading.
- Add `DictCache` class for dict-based cache.
- Add resiliency option to `TwoLevelCache`.
- Add extended `cached` decorator with `in` and `del` support.
- Use base85 instead of base64 for MemCached keys.
- Improved documentation following diátaxis advices.
- Hide some private internals.

- Switch to `pyproject.toml` only.
- Require Python *3.10+* for easier typing.

- documentation updates, especially for `github.io`
- github CI updates
- add `pyproject.toml` (stupid) file

- test with Python *3.12*.

Checked with GitHub CI.