Create CODEOWNERS (#2417)

https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners

Allows automatically assigning PRs to teams/users when it modifies a 
specific section of the repo that they "own".

.github/CODEOWNERS

@@ -0,0 +1,15 @@
+# Default and lowest precedence. If none of the below matches, @iv-org/developers would be requested for review.
+* @iv-org/developers
+
+docker-compose.yml @unixfox
+docker/ @unixfox
+kubernetes/ @unixfox
+
+README.md @thefrenchghosty
+config/config.example.yml @thefrenchghosty @SamantazFox @unixfox
+
+scripts/ @syeopite
+shards.lock @syeopite
+shards.yml @syeopite
+
+src/invidious/helpers/youtube_api.cr @SamantazFox