Add ADT Destructors

[Drodt]

Intended Change

This PR adds deconstructors for ADTs defined in KeY files. Let's say you have a file like

\datatypes {
  List = Nil | Cons(any head, List tail)
}

Previously, a sort List and two functions List Nil and List Cons(any, List) were generated. Now, we also define two additional functions: any head(List) and List tail(List), with the additional rules head(Cons(h, t)) = h and tail(Cons(h, t)) = t.

Additionally, we now raise exceptions, when ADT definitions overwrite functions defined elsewhere. If two deconstructors should be defined, an exception is also raised. But, two deconstructors with the same name and return type are permitted.

Type of pull request

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] Refactoring (behaviour should not change or only minimally change)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] There are changes to the (Java) code
• [ ] There are changes to the taclet rule base
• [ ] There are changes to the deployment/CI infrastructure (gradle, github, ...)
• [ ] Other:

Ensuring quality

• [x] I made sure that introduced/changed code is well documented (javadoc and inline comments).
• [x] I made sure that new/changed end-user features are well documented (https://github.com/KeYProject/key-docs).
• [x] I added new test case(s) for new functionality.
• [x] I have tested the feature as follows: Added proof files.
• [ ] I have checked that runtime performance has not deteriorated.

Additional information and contact(s)

The contributions within this pull request are licensed under GPLv2 (only) for inclusion in KeY.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 94.36620% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 37.90%. Comparing base (1fb0c10) to head (9f72a2d).

Files	Patch %	Lines
.../key/nparser/builder/FunctionPredicateBuilder.java	71.42%	3 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #3420 +/- ## ============================================ + Coverage 37.77% 37.90% +0.13% - Complexity 17031 17064 +33 ============================================ Files 2076 2076 Lines 126950 127017 +67 Branches 21381 21388 +7 ============================================ + Hits 47952 48152 +200 + Misses 73092 72957 -135 - Partials 5906 5908 +2 ```

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