feat(ocm): add openApi schema and OpenApiRouter

[dzemanov]

Description:

Introduces openapi schema for ocm-backend.
Introduces autogeneration of openapi documentation via yarn build:api-docs
Introduces openapi-utils dependency that adds:

• A typed express router
  Some examples:
  
  
  (When openapi.yaml specifies endpoint /example that requires name query param.)
• Validation and verification tooling
  For example when calling /example endpoint without name:

 curl -X GET http://localhost:7007/api/ocm/hello                                                                                                                          ─╯
{"error":{"name":"InputError","message":"request/query must have required property 'name'","stack":"InputError: 
...

2024-08-13T14:48:35.814Z backstage error Request failed with status 400 request/query must have required property 'name' type=errorHandler cause=undefined name=InputError stack=InputError: request/query must have required property 'name'
    at /home/dzemanov/Projects/janus/backstage-plugins/node_modules/@backstage/backend-openapi-utils/dist/index.cjs.js:23:10
    at handleReturn (/home/dzemanov/Projects/janus/backstage-plugins/node_modules/express-promise-router/lib/express-promise-router.js:24:23)
...

• option to autogenerate client code like Apis via:
  yarn backstage-repo-tools package schema openapi generate client --client-package <directory>
  For ocm, this command could be run when inside ocm-backend folder:
  yarn backstage-repo-tools package schema openapi generate client --client-package plugins/ocm-common
  Example of how this autogenerated code looks like can be seen here:
  https://github.com/backstage/backstage/tree/master/packages/catalog-client/src/generated

• this could be used to generate catalog entities with swagger openapi docs (haven't tried this one yet)
  https://www.npmjs.com/package/@backstage/plugin-catalog-backend-module-backstage-openapi

The openapi.generated.ts needs to be regenerated when openapi schema changes via running:
yarn build:api-server .
"@backstage/repo-tools"` must be installed in root workspace for it to run.

Reference: https://backstage.io/docs/openapi/01-getting-started/

Fixes:

RHIDP-3570

[PatAKnight]

Tested and everything works!

One suggestion and one question for you.

[dzemanov]

One thing I would mention is that I didn't add security to openapi.yaml schema because that way openApiRouter checks that requests contain it and for dev development it was giving Error: Authorization header required.

Update: fixed

[PatAKnight]

/lgtm

[PatAKnight]

Looks good, might need to pull in the latest changes to get the CI to pass

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[PatAKnight]

/lgtm