Add StartOS 0.4 package scaffold (manifest, main, interfaces, 2 actions)

- package/Makefile + s9pk.mk + package.json + tsconfig.json
- startos/manifest: dockerBuild source pointing at ../image/Dockerfile
- startos/main: reads /data/config.yaml reactively, passes env vars to container
- startos/interfaces: binds port 9999 as HTTP UI
- startos/actions: showPublicKey (read /data/ssh/id_ed25519.pub), configureSparks
- TS + JS bundle compile clean (tsc --noEmit, ncc build)

package/startos/sdk.ts

@@ -0,0 +1,7 @@
+import { StartSdk } from '@start9labs/start-sdk'
+import { manifest } from './manifest'
+
+/**
+ * Plumbing. DO NOT EDIT.
+ */
+export const sdk = StartSdk.of().withManifest(manifest).build(true)