Do not limit the OIDC scopes

[brianehlert]

When implementing OIDC there are a standard for the base set of scopes: https://openid.net/specs/openid-connect-core-1_0.html#ScopeClaims

The standard allows that additional scopes may be present and should be allowed. And that scope values not understood by an implementation should be ignored. https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest

This implementation enforces the base set of scopes and does not allow for 'additional scopes' - this is achieved through schema enforcement matching. If the scope is not already known an error is reported.

There is a desire allow additional scopes beyond those defined in the specification so that an implementor of the project can define unique or custom scopes beyond those of the standard.

for _, v := range s {
		if !validScopes[v] {
			msg := fmt.Sprintf("invalid Scope. Accepted scopes are: %v", mapToPrettyString(validScopes))
			allErrs = append(allErrs, field.Invalid(fieldPath, v, msg))
		}
	}

Seen here https://github.com/nginxinc/kubernetes-ingress/blob/97da5d3695333f28f16cdc443170ca2231637b7a/pkg/apis/configuration/validation/policy.go

The validation mechanism should be softened to allow for custom scopes.

[brianehlert]

This was addressed by changing the validation logic of the scope names.
The previous behavior enforced the common scopes which had the impact of not allowing additional scopes.