feat: Detect videoplayback proxy from invidious-companion and add it to the CSP header

src/invidious/jobs/backend_checker.cr

@@ -0,0 +1,13 @@
+class Invidious::Jobs::CheckBackend < Invidious::Jobs::BaseJob
+  def initialize
+  end
+
+  def begin
+    loop do
+      BackendInfo.get_videoplayback_proxy
+      LOGGER.info("Backend Checker: Done, sleeping for 60 seconds")
+      sleep 60.seconds
+      Fiber.yield
+    end
+  end
+end