Prioritise filters shown to mobile users

Currently on the smaller screen sizes we show a limited number of dropdown filters on the issuable lists. I think if at some point a user cannot access all of the UI filters then some sort of search syntax should be provided (#18744 (closed)), further on from this it would also be awesome to have a different UI implementation of the filters for mobile so the user can still access all of the filters through UI.

These are big changes however (I may open a ~"feature proposal" for the mobile filter UI depending on how this discussion goes).

A compromise is to prioritise the 3 filters that are shown to smaller screens.

I'm not sure about Author and Assignee, I only ever tend to use these to search for issuables that I myself am authored or assigned to (which is now more easily accessed through the dashboard or the top search input which has epic links like Issues I've created e.t.c). I also think Weight should be replaced with Label.