RFC to remove GlimmerX from Glint

[machty]

I've introduced an RFC to improve/unify Ember language tooling, which recommends removing GlimmerX from the Glint codebase as

1. GlimmerX doesn't appear to be under active development
2. Most Ember devs don't know what it is
3. It'll take time and energy to continue to support
4. It has a flavor of template imports that isn't compatible with goals to leverage TS Plugins rather than language servers for editor tooling

Could I get a GlimmerX maintainer to comment this RFC and validate this plan?

[machty]

GlimmerX has been removed from Glint as of typed-ember/glint#716 (comment)