chore: change all IATP references to DCP

[mspiekermann]

What this PR changes/adds

Change all names and references from IATP to DCP.

Why it does that

As EDWG concluded on a newer naming schema for their protocol and profile projects, the former Identity and Trust Protocol (IATP) was changed to Decentralized Claims Protocol (DCP). EDC's Connector component already handled the IATP as a reference implementation and thus class, variable, etc. names using the IATP abbreviation. With the new name DCP these namings and references must change accordingly.

Further notes

Didn't change the references to IATP in Decision Records.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 60.00000% with 8 lines in your changes missing coverage. Please review.

Project coverage is 75.03%. Comparing base (7f20ba5) to head (5e6140b).
Report is 301 commits behind head on main.

Files	Patch %	Lines
.../identitytrust/core/IdentityAndTrustExtension.java	0.00%	7 Missing ⚠️
...dentitytrust/core/DcpDefaultServicesExtension.java	66.66%	1 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4237      +/-   ##
==========================================
+ Coverage   71.74%   75.03%   +3.28%     
==========================================
  Files         919     1046     +127     
  Lines       18457    20987    +2530     
  Branches     1037     1171     +134     
==========================================
+ Hits        13242    15747    +2505     
+ Misses       4756     4727      -29     
- Partials      459      513      +54     

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