Include token validation for TRS endpoints

[kushagra189]

• Resolve a way for x-bearerInfoFunc to validate tokens. For this, check on ways to include existing FOCA decorator in the TRS-filer.

[uniqueg]

By bumping the FOCA version to 0.6.0 or later, token validation can be handled via the corresponding objects in the OpenAPI specs (securitySchemes and security). After resolving #88, make sure that this works, then report here. If all works as expected, the issue can be closed without any code changes.