Remove Priority protocol

[corverroos]

🎯 Problem to be solved

The priority protocol isn't being used for anything. It has been six months and no use-cases have become apparent. It is best practice to remove code that doesn't add actual value. One can always re-add it later if required.

🛠️ Proposed solution

Remove the priority protocol, infosync, and mutableconfig.

[boulder225]

moving back to parking lot since it is not the major priority anymore.

[pinebit]

We will need this for consensus protocol selection, so no need to remove.