feat: refactor IATP Credential validation into separate service

[paullatzelsperger]

What this PR changes/adds

Separates the cryptographic verification of VPs and VCs and the subsequent checking of several rules into a lower level aggregate service called VerifiableCredentialValidationService.

This reduces the number of collaborators needed by the IdentityAndTrustService and keeps concerns neatly confined.

Why it does that

The main reason for this is that this new service can then be used independently from IATP, e.g. for stand-alone validation of a VP.

Further notes

List other areas of code that have changed but are not necessarily linked to the main feature. This could be method
signature changes, package declarations, bugs that were encountered and were fixed inline, etc.

Linked Issue(s)

Closes # <-- insert Issue number if one exists

Please be sure to take a look at the contributing guidelines and our etiquette for pull requests.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.14286% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 74.69%. Comparing base (7f20ba5) to head (bc27331).
Report is 211 commits behind head on main.

Files	Patch %	Lines
...als/spi/VerifiableCredentialValidationService.java	0.00%	1 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4107      +/-   ##
==========================================
+ Coverage   71.74%   74.69%   +2.94%     
==========================================
  Files         919      981      +62     
  Lines       18457    20098    +1641     
  Branches     1037     1132      +95     
==========================================
+ Hits        13242    15012    +1770     
+ Misses       4756     4592     -164     
- Partials      459      494      +35     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.