Restructure project directories (#333)

`/client/web` -> `/frontend`
`/client/cli` -> *delete for now*
`/client/native` -> *delete for now*
`/core/editor` -> `/editor`
`/core/document` -> `/graphene`
`/core/renderer` -> `/charcoal`
`/core/proc-macro` -> `/proc-macros` *(now plural)*

vetur.config.js

@@ -9,5 +9,5 @@ module.exports = {
 	},
 	// **optional** default: `[{ root: './' }]`
 	// support monorepos
-	projects: ['./client/web']
+	projects: ['./frontend']
 }