JMAP support

[gabriel-lucas]

Hi again Ivan,

I open this other issue related with a new protocol I discovered yesterday. JMAP
There are also JSContact and JSCalendar standards

It is a IETF standar, it has many advantages in comparison with IMAP.

It would be very nice to study it and support it

[Ivan-Malinovski]

That's an interesting proposition.

On one hand, it's a niche within a niche. There's already a limited amount of CalDAV users, and even fewer JMAP/JCalendar users.

On the other hand, being one of the few calendar clients to support it would be cool.

I'll definitely look into this.