WebView2 shell initial release

[Ivshti]

Related to https://github.com/Stremio/labs/issues/24 and more specifically this

build a shell version specifically for Windows using webview2, starting from this prototype: TODO

TODO:

• IPC communication primitives; does not have to be compatible with the old shell, as we can easily adapt the front-end JS, but it needs to be bidirectional and asynchronous message passing
• Implement all the MPV-related IPC commands and events
• Caching,and persistence: https://docs.microsoft.com/en-us/microsoft-edge/webview2/concepts/user-data-folder
• Launch server.js and set the process as a job
• WebView2 settings: disable zoom, status bar, default ctx menu, etc.
• Autoupdater: download the exe, verify it and execute it on demand
• Inhibit screensaver while playing (SetThreadExecutionState)
• Full screen
• Tray icon
• Hide the webview2 while it's not needed through an IPC signal (set_visible(false)); then show it again on user interactions (mouse move, window resize or status change)
• Auto install webview2 if needed: https://github.com/sopium/webview2/blob/751bc32464bf9775516efe392612f0002cb227a3/examples/win32.rs#L37
• Drag and drop
• Ability to be used for opening files (arg1?)

Other things to consider:

• Think whether we can benefit from a "real" DB outside of the regular web persistence technolologies (localStorage and etc.) which we can use through IPC
• Custom mpv build to make it lighter
• To analyze whether MPV performance is worse with --wid, we can compare detailed stdout between pure mpv and the shell
• Maybe NWG has event loop shit we can optimize
• Set thread status as a media thread: https://docs.microsoft.com/en-us/windows/win32/procthread/multimedia-class-scheduler-service or THREAD_PRIORITY_TIME_CRITICAL ; see https://chromium.googlesource.com/external/webrtc/stable/src/+/b9926c7c5cfbcbb7eda871df38c58741d7423739/modules/audio_device/win/audio_device_core_win.cc#2824