chore: updated docs and Helm chart for release

[github-actions]

This PR prepares the docs and the Helm chart for IRS release 5.2.0. Please check whether everything was updated correctly. Once this PR is merged, you can draft a new release. Releasenotes

### Fixed

- Fixed ESS Investigation job processing not starting #579
- Policy store API returns 'rightOperand' without 'odrl:' prefix now (see traceability-foss/issues/970).
- Fixed trivy workflow to fail only on CRITICAL, HIGH (according to https://github.com/eclipse-tractusx/eclipse-tractusx.github.io/pull/949/files).

### Changed

- Improved policy store API input validation. #528
- Extended datamodel of EdcPolicyPermissionConstraint to include andConstraints
- Marked createAccessPolicy requests with deprecation mark.
- Remove edc namespace from EdcContractAgreementNegotiationResponse and
  EdcContractAgreementsResponse. eclipse-tractusx/traceability-foss#963
- Added missing @context values in edc asset creation. eclipse-tractusx/traceability-foss#978
- Switch to `dct:type` `https://w3id.org/catenax/taxonomy#` for notification asset creation. eclipse-tractusx/traceability-foss#978
- Shells in Job response will contain all submodel descriptors returned by provider, instead filtered by aspect-type parameter. #510
- Updated contributing, notice, and readme files for TRG 7 #681
- Handling of expired policies when approving a notification eclipse-tractusx/traceability-foss#639

## Added

- Added tests for aspect version compatibility. #529
- Added endpoint for dedicated removal of policy from BPNL. #559
- Integration Test Policy Store API Unhappy Path. #519
- Support for SingleLevelUsageAsPlanned. #470
- Documentation to describe the delegate process. #470
- Added file for CC BY 4.0 license for TRG 7 #681

**Full Changelog**: https://github.com/ds-jhartmann/item-relationship-service/compare/5.1.4...5.2.0