feat: initialize issuance of SD-JWT credentials

[nanderstabel]

Description of change

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Links to any relevant issues

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How the change has been tested

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Definition of Done checklist

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• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have successfully tested this change in a docker environment

[codecov-commenter]

Codecov Report

❌ Patch coverage is 37.89174% with 218 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
agent_issuance/src/credential/aggregate.rs	47.22%	114 Missing ⚠️
...t_api_http/src/v0/issuance/ietf_oauth_sd_jwt_vc.rs	0.00%	31 Missing ⚠️
agent_secret_manager/src/subject.rs	4.54%	21 Missing ⚠️
agent_issuance/src/state.rs	0.00%	16 Missing ⚠️
agent_shared/src/config/mod.rs	0.00%	15 Missing ⚠️
agent_issuance/src/server_config/aggregate.rs	47.36%	10 Missing ⚠️
agent_api_http/src/v0/issuance/error.rs	0.00%	8 Missing ⚠️
agent_identity/src/document/aggregate.rs	0.00%	3 Missing ⚠️

Files with missing lines	Coverage Δ
...tp/src/v0/issuance/credential_issuer/credential.rs	97.04% <100.00%> (+0.03%)	⬆️
agent_api_http/src/v0/issuance/mod.rs	100.00% <100.00%> (ø)
agent_authorization/src/services.rs	100.00% <100.00%> (ø)
agent_holder/src/presentation/aggregate.rs	81.94% <100.00%> (ø)
agent_holder/src/services.rs	85.00% <100.00%> (ø)
agent_issuance/src/credential/event.rs	0.00% <ø> (ø)
agent_issuance/src/credential/views/mod.rs	100.00% <100.00%> (ø)
agent_issuance/src/services.rs	100.00% <100.00%> (ø)
agent_secret_manager/src/service.rs	100.00% <ø> (ø)
...erification/src/authorization_request/aggregate.rs	92.53% <ø> (ø)
... and 9 more

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