chore: move IATP Transformer Extension into IATP module

[paullatzelsperger]

What this PR changes/adds

Moves the IdentityAndTrustTransformExtension into the identitytrust-core module.

Why it does that

to be able to use several of the VP/VC transformers independently of IATP and of each other.

Further notes

makes the rule that checks the audience optional, and only validates if the expected audience is non-null.

Linked Issue(s)

Closes # <-- insert Issue number if one exists

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 66.58%. Comparing base (7f20ba5) to head (aea2674).
Report is 212 commits behind head on main.

Files	Patch %	Lines
...fiablecredentials/jwt/JwtPresentationVerifier.java	0.00%	7 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4110      +/-   ##
==========================================
- Coverage   71.74%   66.58%   -5.16%     
==========================================
  Files         919      981      +62     
  Lines       18457    20101    +1644     
  Branches     1037     1132      +95     
==========================================
+ Hits        13242    13385     +143     
- Misses       4756     6259    +1503     
+ Partials      459      457       -2     

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