Add static typechecker to pre-commits and tests

[mmschlk]

We should add mypy static type checking. This will however need some changes in what typehints we currently are using. Especially there will be problems/changes with current np.ndarry[int] kind of hints.

• [ ] Add mypy support to pre-commits
• [ ] Adjust codebase typehints to make mypy test green
• [ ] Add mypy test to CI this should be done after or also in #45
• [ ] Edit description in CONTRIBUTING.md

[mmschlk]

While this is an important issue it may be out of scope for the initial version of SHAPIQ

[mmschlk]

Removed and set out of scope