license / docs pass:

- add new docs for loading, exploring, sharing, embedding, and offline usage
- add license file / license banner

electron app:
- for now, don't bundle docs, open in native browser

embeds:
- support 'embed' option, 'replayonly' or 'full' (default if no url)

ui:
- display package.json version in info menu

package.json:
- update scripts to match README
- move electron entrypoint into extraMetadata
- add scripts for packaging as module

README: minor edits

docs/reference.md

@@ -1,11 +1,11 @@
 ---
 layout: default
 title: Reference
-nav_order: 2
+nav_order: 3
 has_children: true
 permalink: /docs/reference
 ---
 
 ## Reference
 
-A guide to the file formats, source locations and query arguments supported by ReplayWeb.Page
+A guide to the file formats, specifications, source locations and other APIs to be supported by ReplayWeb.Page