TODO:

- errors should be precise and dedicated (have their own dedicated message ID)
- verify
  * (server) accept only acceptable domains
    * DONE: right domains
    * TODO: not reserved sub-domains
  * (server) request errors
  * (server) Resource Records to add, del and modify
  * (server) Zone validity on modification
  * (client) check for errors in the list of possible returned messages

DONE:

- domain new (simple domain, not an entire zone)
- domain del + zone del (alias)
- RR entries can be read only
- handle different domains (netlib.re, codelib.re, etc.)
- use a template zone when adding a domain