Some application tags should be reserved to internal usage, even if that usage need is not existing today, mimicking the port allocations for TCP and UDP (e.g. 0-64)

Description

Internal application tags should be for now ignored by the applications and not processed further.

Relevant issues

A possible feature that could benefit from the future allocations could be #5678

Definition of DONE

The reserved application tags:

• cannot be used to send a message through the API
• cannot be popped from the inbox through the API
• are ignored by the applications for now