Refactor rclone-http into a module

[joinemm]

Replaced copypasted rclone-http services with a reusable module, with configurable options. The caddyfile workaround is also removed as the fix has been merged into nixpkgs and backported to our version.

[henrirosten]

Possibly related to the below comments, in testing this configuration, I see the caddy service on binary-cache VM fails to start with the following error:

Apr 05 05:06:53 ghaf-binary-cache-henrirosten systemd[1]: Starting Caddy...
Apr 05 05:07:03 ghaf-binary-cache-henrirosten caddy[955]: {"level":"info","ts":1712293623.4792607,"msg":"using provided configuration","config_file":"/etc/caddy/caddy_config","config_adapter":"caddyfile"}
Apr 05 05:07:03 ghaf-binary-cache-henrirosten caddy[955]: Error: adapting config using caddyfile: server block without any key is global configuration, and if used, it must be first
Apr 05 05:07:03 ghaf-binary-cache-henrirosten systemd[1]: caddy.service: Main process exited, code=exited, status=1/FAILURE
Apr 05 05:07:03 ghaf-binary-cache-henrirosten systemd[1]: caddy.service: Failed with result 'exit-code'.
Apr 05 05:07:03 ghaf-binary-cache-henrirosten systemd[1]: Failed to start Caddy.

Did it work in your tests? I see this error when deploying to a new environment (previously unexisting environment).

[joinemm]

It seems I removed one line too many when getting rid of the workaround. systemd.services.caddy.serviceConfig.EnvironmentFile = "/var/lib/caddy/caddy.env"; is still needed for the environment variables to load. Caddy service was failing because the $SITE_ADDRESS was empty.