~aleteoryx/lfm_embed

ref: e9ca1e6b14fe635fb940f5bae8560c68acca3d12 lfm_embed/src/theming d---------
Document lua, fix small theme bugs
Lua dev mode functional
Lua support feature-complete

Full implementation of debug mode still pending
lua loading
html.lua functional
Start of Lua support
Add SPDX info to all files
Theming refactor

Theming has been broken off into a seperate space, so that it'll be easier to add lua support later.