EasyMDE toolbar is broken

[wxiaoguang]

Related to #24471

I think we should keep EasyMDE, or at least find an alternative. Because when writing Wiki page, it is useful.

[silverwind]

I thought #24448 had replaced all these toolbar icons, but apparently only some. I guess we should restore with octicons.

[yardenshoham]

#24448 removed direct references, not indirect ones. This probably broke after #24471

[yardenshoham]

Shouldn't easymde ship its own font-awesome? Do we override its internal classes?

[wxiaoguang]

We can manually construct every toolbar button, to use other icon sets.

[silverwind]

Yes, my oversight there. If the restoration is too much work, we could drop EasyMDE as well.

Shouldn't easymde ship its own font-awesome? Do we override its internal classes?

No, it apparently has an option autoDownloadFontAwesome which downloads it from CDN, but of course we needed to disable that as we don't want such downloads to happen.