Support for synchronized & backed up settings

[saledjenic]

There are lot of settings' items added to syncing & backing up mechanism (though some are just added to one of those two). Another fact is that desktop app handling is applied for some of them only, not for all.

This issue should align all that (add item to sync and/or backup mechanism and add desktop app handling if not implemented).

item	added to sync	added to backup	handled in desktop	comment
currency	✅	✅	✅	was partially handled, now completed in commit
display_name	✅	✅	✅	was partially handled, now completed in commit
bio	✅	✅	✅	was partially handled, now completed in commit
gif_favorites	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
gif_recents	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
messages_from_contacts_only	❓	❓	❓	not in use or not yet in desktop app
mnemonic_removed	✅	✅	✅	was partially handled, now completed in commit
preferred_name	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
preview_privacy	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
profile_pictures_show_to	new issue	new issue	new issue	there is UI only, BE is missing, will be done with BE implementation
profile_pictures_visibility	new issue	new issue	new issue	there is UI only, BE is missing, will be done with BE implementation
send_status_updates	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
stickers_packs_installed	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
stickers_packs_pending	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
stickers_recent_stickers	❌	❌	❌	excluded from syncing because of status-im/status-mobile#13053 (comment)
usernames	❓	❓	❓	not in use or not yet in desktop app