Make the nebula wizard embed-able

[geofmureithi]

Describe the solution you'd like
I would want to be able to pragmatically embed a contract. This would generate the usual invoke and similar commands.

Consider such an example:

<script src="path/to/embedded.js"/>
<div id="container"></div>
<script>
  let nebula = new NebulaEmbed({
       pulsarUrl: "some/path",
       contract: "some/git/path"
  });
  nebula.bind("container");
</script>

A Remix button can be included to redirect to the pulsar IDE.

Additional context
We can borrow more context from other similar embed-able wizards.

[geofmureithi]

How would this work?

• Create a comprehensive component for the CodeEditor
• Allow the component to be usable by both projects.
• Allow compiling the component as a stand alone javascript file.

[geofmureithi]

An alternative to the code syntax above:

<script 
    src="path/to/embed.js" 
    data-pulsar-url="/path" 
    data-contract-url="some-git-path" 
    data-bind-to="#container"
/>

References:
https://stackoverflow.com/questions/49626885/embedding-reactjs-in-remote-site-iframe
https://stackoverflow.com/questions/326069/how-to-identify-if-a-webpage-is-being-loaded-inside-an-iframe-or-directly-into-t