feat: Add experimental rewrite of go2rtc live provider (MSE/WebRTC/MP4/MJPEG) (#2580)

- Closes #2556
- Closes #2450

**Key intended features:**
 - go2rtc compatible
- 100% test coverage to significantly improve ability to test, maintain
and work around browser weirdnesses (e.g. Safari).
 - Written from the ground up in the style of the rest of the project.

**To use:**
 - Change `live_provider` from `go2rtc` to `go2rtc-experimental`.

tests/components-lib/live/providers/go2rtc-experimental/utils/messages.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from 'vitest';
+
+import { isServerErrorForMode } from '../../../../../../src/components-lib/live/providers/go2rtc-experimental/utils/messages';
+
+describe('isServerErrorForMode', () => {
+  it('should match an error for the mode', () => {
+    expect(isServerErrorForMode({ type: 'error', value: 'mse: not found' }, 'mse')).toBe(
+      true,
+    );
+  });
+
+  it('should not match an error for another mode', () => {
+    expect(isServerErrorForMode({ type: 'error', value: 'webrtc: failed' }, 'mse')).toBe(
+      false,
+    );
+  });
+
+  it('should not match a non-error message', () => {
+    expect(isServerErrorForMode({ type: 'mse', value: 'codecs' }, 'mse')).toBe(false);
+  });
+
+  it('should not match an error with a non-string value', () => {
+    expect(isServerErrorForMode({ type: 'error', value: 42 }, 'mse')).toBe(false);
+  });
+
+  it('should not match an error with no value', () => {
+    expect(isServerErrorForMode({ type: 'error' }, 'mse')).toBe(false);
+  });
+});