Adding back 'hide empty chat rooms' setting, was disabled at some point during 6.0 dev but should be enabled back

Fixed text message description not being italic for some parts + improved description: added duration to voice message & replaced file name by image emoji for pictures

Prevent case causing memory chat room to be re-used as a diffent one, leading to duplicated listener

Prevent crash in CoreFileTransferService if Core's thread is busy and doesn't trigger notification fast enough

Fixed duplicated phone numbers in loaded contacts from native addressbook + improved code by factorizing some parts of it

Added a way to choose which friend list to use to store newly created contacts into (for CardDAV friend list for example)