refactor static and asset emission to be actual emitter plugins

quartz/plugins/emitters/static.ts

@@ -0,0 +1,21 @@
+import { globby } from "globby"
+import {
+  FilePath, QUARTZ
+} from "../../path"
+import { QuartzEmitterPlugin } from "../types"
+import path from "path"
+import fs from "fs"
+
+
+export const Static: QuartzEmitterPlugin = () => ({
+  name: "Static",
+  getQuartzComponents() {
+    return []
+  },
+  async emit({ argv }, _content, _resources, _emit): Promise<FilePath[]> {
+    const staticPath = path.join(QUARTZ, "static")
+    const fps = await globby("*", { cwd: staticPath })
+    await fs.promises.cp(staticPath, path.join(argv.output, "static"), { recursive: true })
+    return fps.map(fp => path.join("static", fp)) as FilePath[]
+  },
+})