Trim down unused ipfs-css assets

[lidel]

After switching to ipfs-css v1.x we ballooned the package a bit:

v2.11 (last stable):

10M ipfs_companion-2.11.0_chromium.zip 
4M  ipfs_companion-2.11.0_firefox.zip

v2.11.0.918 (latest beta):

19M   ipfs_companion_beta_ece3e0b_-2.11.0.918_chromium.zip
12M   ipfs_companion_beta_ece3e0b_-2.11.0.918_firefox.zip

Low hanging fruit is to remove fonts and icons that are not used:

 12.2 MiB  /ui-kit/fonts
564.0 KiB  /ui-kit/icons

Another problem is the size of WebUI, which is for now only bundled with Chromium/Brave:

 21.6 MiB  /dist/precache/webui.tar

But that's something we need to tackle upstream.

[jessicaschilling]

I was actually thinking of using the power and gear icons from ipfs-css in the main control screen, so thanks for the heads up ...

[lidel]

@jessicaschilling I mean, some fonts and some icons are being used, we just need to find a way of removing unused ones. In the past, the surface was small, and we used CSS directly, probably should start processing it as part of the build – I will look into this today, as I need to solve it before shipping to stable channel.

(I'd love us to use power and gear as they are in ipfs-css instead of custom versions we have right now)