Annotate all the code with the types

[nolar]

Add type-hints all over the code. Enable strict type-checker.

Issue : #194
Requires #199 first — due to unrelated external changes.

Description

After few preparational refactorings in #195, #196, #197, #198, the code is now ready to get all the type-hints for all the methods.

Generally, there are no behavioural changes. However, in some places, the code is changed to allow the type-checker to properly infer (guess) the type of variables.

The strict-mode type-checker is now a mandatory step of CI/CD. All the new code (functions, methods, classes) since now MUST be type-annotated.

Types of Changes

• Refactor/improvements

[zincr]

🤖 zincr found 0 problems , 1 warning

ℹ️ Large Commits
✅ Approvals
✅ Specification
✅ Dependency Licensing

Details on how to resolve are provided below

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Large Commits

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This file contains a substantial change, please review to determine if the change comes from an external source and if there are any copyright or licensing issues to be aware of

• ℹ️ kopf/reactor/registries.py had +100 lines of code changed in a single commit
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• ℹ️ kopf/reactor/state.py had +100 lines of code changed in a single commit
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• ℹ️ kopf/structs/bodies.py had +100 lines of code changed in a single commit
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