Convert subprojects to git submodules

- haos-integration -> haos-hacs-emby-media-player.git
- media-server -> media-player.git

Each component is now an independent repository that can be
developed and versioned separately.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitmodules

@@ -0,0 +1,6 @@
+[submodule "haos-integration"]
+	path = haos-integration
+	url = https://git.dolgolyov-family.by/alexei.dolgolyov/haos-hacs-emby-media-player.git
+[submodule "media-server"]
+	path = media-server
+	url = https://git.dolgolyov-family.by/alexei.dolgolyov/media-player.git