@param service [Yast2::Systemd::Service] systemd service. Usually the easiest way
is just calling `Yast2::Systemd::Service.find("name_of_the_service")`
Note that this widget will #start and #stop the service by itself but
the actions referenced by the flags (reloading and enabling/disabling)
are expected to be done by the caller, when the whole configuration is
written.
@param reload_flag [Boolean] Initial value for the "reload" checkbox.
Keep in mind it will always be displayed as unchecked if the service
is not active, despite the real value.
@param reload_flag_label [Symbol] Type of label for the "reload" checkbox.
:reload means the service will be reloaded.
:restart means the service will be restarted.
