Electron app loading improvements + Windows paths fix (#429)

- Electron no longer allows Windows paths in URLs
(https://www.electronjs.org/docs/latest/breaking-changes#behavior-changed-custom-protocol-url-handling-on-windows),
fixes with help of wabac.js to replace `C:\path\to\file` with
`C//path/to/file`
- Electron app cleanup: replace deprecated protocol handlers with new
protocol.handle() method, update types
- Electron app: ensure just filename is displayed on index page,
consistent with other platforms
- Update to wabac.js 2.23.2
- Update to Electron 36.3.2
- Fixes #427
- bump to 2.3.12

src/appmain.ts

@@ -639,13 +639,6 @@ export class ReplayWebApp extends LitElement {
     if (this.pageParams.get("swName")) {
       this.swName = this.pageParams.get("swName") || undefined;
     }
-
-    if (IS_APP && this.sourceUrl.startsWith("file://")) {
-      this.loadInfo = {
-        sourceUrl: this.sourceUrl,
-        loadUrl: this.sourceUrl.replace("file://", "file2://"),
-      };
-    }
   }
 
   // @ts-expect-error [// TODO: Fix this the next time the file is edited.] - TS7006 - Parameter 'event' implicitly has an 'any' type.