* create group after invitation
* add group invitation to db, show sent and received group invitations
* test creating group and sending invitation
* establish group connections (WIP)
* connect user to the inviter, notification, member classification
* test adding same contact, add display_names table and functions
* rename display_name -> full_name
* use shared namespace for usernames, contact names and group names
* create group
* add user as member, store methods to get group and to create group member
* add group member and send member invitation
* fix ci: use simplexmq from github
* chat protocol: create SMP agent connection when inviting member
* update protocol, started group invitation receiving
