[Feature] Have somewhere to see all starred messages

[fcoppolani]

Hi,

As for 0.63.1 version starred messages are only per channel/private message. Some users aske for a way of searching all their starred message without selecting a channel. I guess this option should be available only if global search is enabled. I would imagine a checkbox 'starred messages' along with the 'global search' allowing a user to search only amongst his starred message :

could be related to #310 (which has not been totally finished)

Thanks in advance for your help.

Regards,