Add swagger spec and include auth APIs and common APIs

[haoming29]

Closes #352

This is a hand-coded Swagger specification of APIs in Pelican servers. For now, I included APIs for authentication and common APIs (/config, /health, etc.)

As a next step, we might want to programmatically generate this spec using annotations on handler functions, and there's existing Go package to handle spec generation for us: swaggo/swag

If you are using VSCode as your IDE, you can render the Swagger UI from this .yaml file by installing the OpenAPI (Swagger) Editor

[CannonLock]

@haoming29 Is there a reason you picked yaml over json?

I am supposed to consume this in the frontend so it will be more convenient for me to have it as json.

[haoming29]

@haoming29 Is there a reason you picked yaml over json?

I am supposed to consume this in the frontend so it will be more convenient for me to have it as json.

@bbockelm suggested to use yaml to be more human-readable and I thought the swagger-ui npm package support .yaml by default? https://github.com/swagger-api/swagger-ui/blob/HEAD/docs/usage/configuration.md#configuration

[CannonLock]

Okay, yaml works for now. When this is autogenerated we should do JSON as well as yaml.

The npm package only consumes json, its not a hard translation but I don't see any reason to make it if we can auto generate the file. -> https://www.npmjs.com/package/swagger-ui-react

[haoming29]

Okay, yaml works for now. When this is autogenerated we should do JSON as well as yaml.

The npm package only consumes json, its not a hard translation but I don't see any reason to make it if we can auto generate the file. -> https://www.npmjs.com/package/swagger-ui-react

That makes sense to me

[CannonLock]

Approved.

Make sure to add another commit to your auth restructure so that these paths are maintained.