[fix] [example] metadata MUST have trust_mark_issuer

[peppelinux]

I have to move this endpoint to this specialized entity in the TA metadata

The metadata type identifier is trust_mark_issuer.

All entities participating in a federation may be of this type.

The following properties are allowed:

status_endpoint
OPTIONAL. The endpoint for the status operation described ...

"trust_mark_issuer": {
  "status_endpoint": "https://trust_marks_are_us.example.com/status"
}

[peppelinux]

Even the federation entity has the federation_status_endpoint, so we don't have any use case in the example projects to add also this kind of metadata

for now :)