error fix + embedding extensability (#110)

* embed mode: make embedding options more extensible
ui: unify service worker not available errors, show same error in standard/embed mode, including when loaded over http
- more customizations for extended embed, allow hiding 'browse contents' button
- simplify title updates
- make error page / icon more customizable
- autoupdating in editable mode: don't update if previous one didn't finish, make customizable, don't autoupdate at all over >=100 pages

* dependencies: update ruffle to 2022-07-02

* bump to 1.6.1, update CHANGELIST

_data/package.json

@@ -1,7 +1,7 @@
 {
   "name": "replaywebpage",
   "productName": "ReplayWeb.page",
-  "version": "1.6.0",
+  "version": "1.6.1",
   "description": "Serverless Web Archive Replay",
   "repository": "https://github.com/webrecorder/replayweb.page",
   "homepage": "https://replayweb.page/",