add basic embed package

packages/embed/example.html

@@ -0,0 +1,16 @@
+<script src="./embed.js"></script>
+
+<strudel-repl>
+  <!--
+  "a4 [a3 c3] a3 c3".color('#F9D649')
+.sub("<7 12 5 12>".slow(2))
+.off(1/4,x=>x.add(7).color("#FFFFFF #0C3AA1 #C63928"))
+.off(1/8,x=>x.add(12).color('#215CB6'))
+.slow(2)
+.legato(sine.range(0.3, 2).slow(28))
+.wave("sawtooth square".fast(2))
+.filter('lowpass', cosine.range(500,4000).slow(16))
+.out()
+.pianoroll({minMidi:20,maxMidi:120,background:'#202124'})
+  -->
+</strudel-repl>