feat: Standalone STS

[wolf4ood]

What this PR changes/adds

Implements the self-contained version of STS.

In this PR:

The module :extensions:common:iam:identity-trust:identity-trust-sts is created for all STS extensions:

• identity-trust-sts-api API for minting tokens
• identity-trust-sts-client-configuration file based StsClients configuration (testing/simple use case)

To be moved in a subsequent PR into :extensions:common:iam:identity-trust:identity-trust-sts

• identity-trust-sts-core
• identity-trust-sts-embedded

Additionally a sample launcher in launchers/sts-server is created for playing with the STS standalone.

Additional modules are created for E2E testing of the STS in system-tests:sts-api

Why it does that

iatp adoption

Linked Issue(s)

Closes #3499

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[codecov-commenter]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (0afa286) 72.28% compared to head (6b1f608) 72.45%.

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3556      +/-   ##
==========================================
+ Coverage   72.28%   72.45%   +0.16%     
==========================================
  Files         880      887       +7     
  Lines       17724    17846     +122     
  Branches     1022     1023       +1     
==========================================
+ Hits        12812    12930     +118     
- Misses       4476     4480       +4     
  Partials      436      436              

Files	Coverage Δ
...ts/core/defaults/service/StsClientServiceImpl.java	100.00% <100.00%> (ø)
...ts/service/StsClientTokenGeneratorServiceImpl.java	100.00% <100.00%> (ø)
...tor/api/sts/configuration/StsApiConfiguration.java	100.00% <100.00%> (ø)
...ts/controller/SecureTokenServiceApiController.java	100.00% <100.00%> (ø)
...tor/api/sts/exception/StsTokenExceptionMapper.java	100.00% <100.00%> (ø)
...connector/api/sts/model/StsTokenErrorResponse.java	100.00% <ø> (ø)
...e/edc/connector/api/sts/model/StsTokenRequest.java	100.00% <100.00%> (ø)
.../edc/connector/api/sts/model/StsTokenResponse.java	100.00% <ø> (ø)
...r/api/sts/validation/StsTokenRequestValidator.java	100.00% <100.00%> (ø)
...nector/api/sts/SecureTokenServiceApiExtension.java	80.00% <80.00%> (ø)
... and 4 more

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