Add TLD (SIP48) Support

[ohager]

Is your feature request related to a problem? Please describe.
At this moment, TLDs are not supported, i.e. on the alias section, but also inside the recipient input.

Describe the solution you'd like
Add Support - consider also to cancel renewal subscriptions for aliases.

[shefass]

Friendly reminder: we need to agree about aliases notation format so it was consistent on all platforms.
e.g. ohager@signum , ohager:signum, ohager.signum, xxx:yyy:ohager:signum, xxx.yyy.ohager.signum
I think xxx:yyy:ohager:signum looks better then xxx@yyy@ohager@signum and my favorite probably is . e.g. ohager.signum

[ohager]

Thanks. It will be "ohager:signum" "ohager:nostr" - XT Wallet will be adjusted also

About Simple dot annotation: ohager.signum doesn't work as this will conflict with XT Name Resolver and common URLs. Due to the nature of having arbitrary domains now, also ohager.de would be possible.... but the Name Resolver won't be able to understand if this is ICANN ohager.de or Signum Alias.