"View messages sent", from a profile screen

[gnprice]

In Zulip web, after you click on a user's name or avatar, one of the options is "View messages sent". This takes you to a search view showing all the messages (that you can see) that the given user sent.

This is a handy feature, and it'd be good to include on mobile as well. (We don't currently have this in zulip-mobile.) This means a button on the profile screen, just under the "Send direct message" button, which leads to an appropriate message list.

Implementation

A prerequisite issue is:

• msglist: Offer search narrows #252

because the narrow "sent by user X" is effectively a type of search narrow.

The initial version of #252 will cover only searches for plain-text queries, and this will be a search with a different operator. This issue might come after adding general search operators to the search screen, and in that case this issue would be a simple matter of adding a button to the profile screen.

Alternatively, we could take this issue as the initial prompt to begin extending the search screen in that direction. In that case we'd probably keep the changes to the search screen, and to internal abstractions like Narrow subclasses, down to the minimum required to support this feature. We'd leave further extensions to other search operators (and especially the UI to support them in the search screen) for later.