Add endpoint to retrieve resources by resourceIdentifier

[lahabana]

Description

We now have a systematic resourceIdentifier for everything.

There's a hash that should be computed from the resource Identifier. Is there a systematic way to compute the hash from a set of labels?

So could we have a new endpoint:

/meshes/<mesh>/<resourceType>/_resourceIdentifier/zones/<zoneName>/namespaces/<namespace>/name/<displayName>

These would always return the same as:

/meshes/<mesh>/<resourceType>/<hashedName>

This should be a MADR and this MADR should define:

• resourceIdentifier
• hashing algorithm from resourceIdentifier to resourceName
• new api endpoint and how it should be implemented

This endpoint would enable the GUI to map from XDS config to resources and to hide altogether resourceNames to only rely on resourceIdentifier everywhere.

xref: kumahq/kuma-gui#2848