[FEATURE] Proper name handling for KymaEnvironment

[sdischer-sap]

Is your feature request related to a problem? Please describe.
We found in an internal support issue, that the way IDs are managed for KymaEnvironemnt leads to a problem when the instance gets manually updated in the BTP cockpit. In this case the label that is being used to link the k8s resource to the external one gets flashed and thus the resource would no longer be reconciled.

Describe the solution you'd like
I can not really tell why this has been implemented like that initially, but I do not see anything that would prevent us from properly using a GUID as external-name annotation for the connection. It should be the default approach to any crossplane instance. I suggest to implement it like that but of course ensure the backwards compatibility here.

Describe alternatives you've considered
There might be other identifiers that can be used, but we need to have something in the k8s resource for identification and not vice versa.