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

src/appmain.js

@@ -162,6 +162,10 @@ class App extends LitElement
             <div class="navbar-item">
               Collection Id:&nbsp;<b>${this.collInfo.coll}</b>
             </div>
+            <hr class="navbar-divider">
+            <div class="navbar-item">
+              ReplayWeb.page Version: ${__VERSION__}
+            </div>
           </div>
         </div>
         ` : ``}