Support recording audio in web

[lukexor]

Desktop supports recording audio .wav files to the users music directory based on OS without user interaction. In web, downloading files requires the user to interact with the page.

This could be done by showing a message with a 'Download' button when the recording is stopped, allowing the user to download it or discard it.

Some reference JS code for how this might work (will need to be converted to Rust):

const blob = new Blob([binEncodedData], {
  type: "application/octet-stream",
});

const url = URL.createObjectURL(blob);
const a = document.createElement("a");
a.href = url;

a.download = "demo.replay";
document.body.appendChild(a);
a.click();

document.body.removeChild(a);
URL.revokeObjectURL(url);