Additional options to hide favicons

**Is your feature request related to a problem?**

I would like to be able further customize hiding favicons: https://github.com/black7375/Firefox-UI-Fix/wiki/Options#tab-icon

**The solution I'd like**

- Only show favicons for pinned tabs and the active tab [optional]
- Only show favicons for pinned tabs and Firefox Home / New Tab page + other internal pages (settings, `about:___`, etc.) **[I really like this]**
- Only show favicons for pinned tabs, active tab, and new tab / internal pages [optional]

For those who want something less extreme, show favicons on all tabs (i.e. default behavior), but:
- Favicon only for background tabs / No favicon on active tab **[I really like this]**
- Collapse favicon upon mouse hover

**Screenshots or video**

**Alternatives I've considered**

[This](https://www.reddit.com/r/FirefoxCSS/comments/infnnc/how_to_completely_disable_or_change_the_favicons/) but it is outdated.

**Additional context**

Start by reviewing the issue's Firefox-UI-Fix wiki link for the existing tab-icon options and compare them with the requested favicon behaviors. The work is done when the supported options for pinned, active, internal, background, and hovered tabs are implemented and documented, with each requested visibility mode behaving as described.

Written by the indexing model from the issue text.