Feature: support multiple filters added via bindings with repeat key presses toggling the filter

[benelan]

Description

Only one filter can be applied at a time, and adding another removes the first. Filters should be stackable like they are on GitHub.

Acceptance Criteria

1. Adding additional filters do not remove the ones already applied
2. The bindings toggle filters on/off with multiple key presses

Relevant Info

With the scripts current design, this will likely require saving state to the filesystem, or potentially environment variables.

gh-fzf is getting too complicated for a shell script, so I'm considering a go rewrite using one of these libraries:

• https://github.com/cli/go-gh
• https://github.com/google/go-github
• https://github.com/shurcooL/githubv4

Example Use Case

1. run gh fzf issue
2. press alt-a to show the issues or pull requests assigned to you
3. press alt-s to show both open and closed issues
4. notice the assignee filter was removed

The current workaround is to start gh-fzf with one of the filters, e.g.

gh fzf issue --assignee @me