api: enhance error reporting with custom error codes and messages

[Piiit]

• @Piiit checks if it is related to the deployment (proxy, redirects or authentication)
• if not, @SirCotare will fix the bug --> return the correct error code and message
• as stated in the comments, the error messages are sometimes wrong or too noisy

[Piiit]

@SirCotare @danielecanu
I checked this now, and it seems that when no 'Authorization' header is attached to the call the following error message is shown:

{
  "errorCode": 400,
  "message": "Request method 'PATCH' not supported",
  "stacktrace": ""
}

This is misleading I think, we should instead show an unauthorized error code and message. Could you please fix that?

With the Bearer token headers the PATCH commands seem to work (tested only with /admin/webcomponent/f594de36-0136-4c27-a0e6-570fa7014129/v1.8.1/metrics)

[Piiit]

@SirCotare It seems that this is somehow the "default" error message... If I send a wrong JSON with a call, it does not show that the payload is wrong but also "PATCH not supported error"

[Piiit]

We will check this with #148

[Piiit]

I tested this and the PATCH error is no longer wrongly shown, however the error messages are still very noisy...

For example:

POST /admin/webcomponent/f594de36-0136-4c27-a0e6-570fa7014129
Content-Type: application/json
Authorization: Bearer {{token}}

shows

{
  "errorCode": 400,
  "message": "Validation failed for argument [1] in public it.bz.opendatahub.webcomponents.dataservice.application.adapter.in.web.admin.rest.WebcomponentVersionAdminRest it.bz.opendatahub.webcomponents.dataservice.application.adapter.in.web.admin.WebcomponentVersionAdminController.createNewVersion(java.lang.String,it.bz.opendatahub.webcomponents.dataservice.application.port.in.CreateWebcomponentVersionUseCase$WebcomponentVersionCreateRequest): [Field error in object 'webcomponentVersionCreateRequest' on field 'configuration': rejected value [null]; codes [NotNull.webcomponentVersionCreateRequest.configuration,NotNull.configuration,NotNull.it.bz.opendatahub.webcomponents.common.data.struct.Configuration,NotNull]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [webcomponentVersionCreateRequest.configuration,configuration]; arguments []; default message [configuration]]; default message [must not be null]] ",
  "stacktrace": ""
}

if a wrong JSON format has been given. Those error messages should not just pass-thru whatever the exception throws, but give a meaningful hint to the API user.

[Piiit]

The nice user-facing error messages needs to be written custom and not just passed through the Bean validation tooling. It is not easy to implement, needs a lot of work, and is not blocking. Therefore, we decided to implement it in a future iteration...

To be clear, related bugs are solved