Update to protovalidate & properly validate for namespaces

[lennysgarage]

PR Template:

Describe your changes

• Upgrade from protoc-gen-validate to protovalidate
• • proto files validation updated
• • no longer uses validate.go files
• • Requests are now recursively validated through all embedded sub-messages
• Updated ALL tests with a "rbac" namespace as required by our proto spec
• Validation removed from service components to validation middleware to handle all validation requests
• • Added test cases for validation middleware in validation_test.go
• • Removed test cases that were just covering validation aspects of old service code. (TestLookupService_LookupSubjects_EmptyRequest, TestLookupService_LookupResources_EmptyRequest, TestLookupService_LookupResources_Empty)

When missing namespace:

ERROR:
  Code: InvalidArgument
  Message: validation error:
 - resource.type.namespace: value length must be at least 1 characters [string.min_len]
 - subject_type.namespace: value length must be at least 1 characters [string.min_len]
  Details:
  1)	{
    	  "@type": "type.googleapis.com/google.rpc.ErrorInfo",
    	  "reason": "Invalid request"
    	}

Ticket reference (if applicable)

Fixes # RHCLOUD-33724

Checklist

• Are the agreed upon acceptance criteria fulfilled?

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• Do your changes have passing automated tests and sufficient observability?

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  • An SOP (Standard Operating Procedure) was created

• The Changes were automatically built, tested, and - if needed, behind a feature flag - deployed to our production environment. (Please check this when the new deployment is done and you could verify it.)

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• Are security needs fullfilled? (e.g. no internal URL)

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• For changes to the public API / code dependencies: Was the whole team (or a sufficient amount of ppl) able to review?

[merlante]

Well done, nicely handled with the middleware tests!

LGTM