Add hotkeys for filter-expr and also add keys to create a new expr in the filters view #1599
Description
Is your feature request related to a problem? Please describe.
filter-expr is one of the more powerful features to pare down large logs considering that lnav actually parses them so you can filter by specific fields. But I think it is not exposed and visible well enough in the UI currently.
Describe the solution you'd like
Add hotkeys for the :filter-expr command to make it more readily accessible, and also add keys to create/edit the filter-expr in the filters view (TAB).
Describe alternatives you've considered
Keep typing :filter-expr or bind my own key for it.
Additional context
It would be interesting making the feature even more powerful of course, such as multiple expressions that you can quickly toggle on-off, more quick ways to create expressions and so on. But that needs some good design to make it useful. e.g. Looking at some other log analysis tools to see how they work and how they combine stuff in their filtering/query language.