Kaithem

- :coffin: Remove a lot of dead code
- :coffin: :fire: BREAKING: Remove the entire VirtualResource mechanism. I think it was too complicated to use anyway.
- As a result, getting a Device object will give a Weak Proxy to the device instead of a VirtualResourceInterface.
- REMINDER: When accessing a Device, tagpoint, etc, don't keep a reference to somthing a user could update and replace!
access kaithem.devices['foo'] directly rather than making a local reference.
- Tag Points and the Message Bus are the official ways to do loose coupling, and are much simpler.
- :bug: Fix inability to create new device inside a module
- :coffin: Theming, alert tones, and server locations use files in core.settings. Registry data is auto migrated.
- :sparkles: New kaithem.persist.unsaved dict for user-created files to inform the UI of unsaved changes.
- :fire: Announce that the registry will be deprecated eventually. Modules should attempt to move data to files instead.
- :coffin: Remove mailing list features, as they were very old, unmaintained, and email is a security critical feature.
- :coffin: Remove kaithem.serial. It was unmaintained and never production-tested, and not used internally here in a very long time.
- :coffin: Remove the restart server option. On newer systems it would sometimes just stop and not restart.

- :lock: SECURITY: Can no longer do certain things in a cross-origin iframe, as extra protection.
- :lock: SECURITY/BREAKING: Now you need a POST request for Chandler's sendevent API
- :lock: :sparkles:SECURITY: User pages show at a glance whether they accept GET
- :bug: Fix inability to assign new user-created permissions to users or pages.
- :sparkles: This file uses GitMoji now! Gitmoji chosen because it is the first Google result.

- SECURITY/SEMI-BREAKING: No CORS requests from any other domain allowed as a user, regardless of permissions needed, unless enabled in user settings.
- SECURITY: Fix bug where an attack from my.org could be accepted as matching your domain at my.org.fooo.com
- Fix old code that was looking for YOLOv3.txt

- kaithem.web.serveFile streaming response
- SECURITY: Beholder no longer allows unauthorized access to camera snapshots
- Correctly finalize M3U8 files with the end playlist tag

- Clean up a process leak with the IceFlow servers

- Correctly compute width and height of deteted objects