add pid file to systemd unit and move services to data folder

data/systemd/meson.build

@@ -0,0 +1,17 @@
+systemd_config_data = configuration_data()
+systemd_config_data.set('LIBEXECDIR', join_paths(get_option('prefix'), get_option('libexecdir'), meson.project_name()))
+
+systemd_config_data_file = configure_file(
+    input: 'tufmanager.service.in',
+    output: 'tufmanager.service',
+    configuration: systemd_config_data
+)
+
+systemd = find_program ('systemd', required: false)
+
+if systemd.found()
+    install_data(
+        systemd_config_data_file,
+        install_dir: join_paths(get_option('prefix'), 'lib', 'systemd', 'system')
+    )
+endif

data/systemd/tufmanager.service.in

@@ -0,0 +1,10 @@
+[Unit]
+Description=TUF Manager Server
+
+[Service]
+Type=forking
+PIDFile=/run/tufmanager/pid
+ExecStart=@LIBEXECDIR@/tuf-server
+
+[Install]
+WantedBy=multi-user.target