Introduce Type Alias for Patterns and more

[noklam]

Background

As a follow up action, we agreed to introduce type like Patterns = Dict[str, Dict[str, Any]] to improve the readability of the code a lot.

An example can be found here

We can also do this beyond just Patterns but to more complicated types within the code base.

As discussed, let's separate the Type Alias proposed in #2770.
I will close #2770 and approve this PR now. :)

Originally posted by @noklam in #2635 (comment)

[noklam]

This could be nicely rewritten to:

matches = (parse(pattern, data_set_name) for pattern in data_set_patterns.keys())
return next(filter(None, matches), None)

Originally posted by @idanov in #2635 (comment)

There are some minor refactoring work linked here, we can address this with this change.

[noklam]

Closed with #2779