search by date
Some Mattermost instances have many channels and a crazy number of posts, leading to searches on terms returning too many results. It would be good to be able to search by date range. For example, gmail uses after:yyyy-mm-dd before:yyyy-mm-dd and probably other date formats to enable searching by date.
Another way to name those could be "since:YYY-MM-DD"" and "until:YYYY-MM-DD"