feat(api-hub): create open api spec on build

[Phil91]

Description

Generate open api spec on build of the issuer service

Why

To align with TRG 1.08

Issue

Refs: #256

Checklist

• I have followed the contributing guidelines
• I have performed IP checks for added or updated 3rd party libraries
• I have created and linked IP issues or requested their creation by a committer
• I have performed a self-review of my own code
• I have successfully tested my changes locally
• I have added tests that prove my changes work
• I have checked that new and existing tests pass locally with my changes
• I have commented my code, particularly in hard-to-understand areas
• I have added copyright and license headers, footers (for .md files) or files (for images)

[Phil91]

This PR will fail until eclipse-tractusx/portal-backend#1030 is merged, until than it only works with building the nuget packages locally

[sonarqubecloud]

Quality Gate failed

Failed conditions
50.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud

[Phil91]

Quality Gate failed

Failed conditions 50.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud

this can be ignored, the test coverage is mentioned for extension methods which only register settings and a service