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.
I think we should stay close to the definitions that Slack uses. Because sadly you often need to use both at the same time and it would be confusing, using different keywords.
Another way to name those could be "since:YYY-MM-DD"" and "until:YYYY-MM-DD"