ncm-systemd: Add path support

Adds support for [path] directives. This is useful for credential
handling, where we can detect the template file changing and trigger a
one-shot service.

ncm-systemd/src/main/pan/components/systemd/schema.pan

@@ -355,6 +355,24 @@ type ${project.artifactId}_unitfile_config_socket = {
     true;
 };
 
+@documentation{
+the [Path] section
+https://www.freedesktop.org/software/systemd/man/systemd.path.html
+}
+type ${project.artifactId}_unitfile_config_path = {
+    'PathExists' ? absolute_file_path
+    'PathExistsGlob' ? string
+    'PathChanged' ? absolute_file_path
+    'PathModified' ? absolute_file_path
+    'DirectoryNotEmpty' ? absolute_file_path
+
+    'Unit' ? string
+    'MakeDirectory' ? boolean
+    'DirectoryMode' ? type_octal_mode
+    'TriggerLimitIntervalSec' ? string
+    'TriggerLimitBurst' ? long(0..)
+}
+
 @documentation{
 the [mount] section
 http://www.freedesktop.org/software/systemd/man/systemd.mount.html
@@ -421,6 +439,7 @@ type ${project.artifactId}_unitfile_config = {
     'socket' ? ${project.artifactId}_unitfile_config_socket
     'mount' ? ${project.artifactId}_unitfile_config_mount
     'automount' ? ${project.artifactId}_unitfile_config_automount
+    'path' ? ${project.artifactId}_unitfile_config_path
     'timer' ? ${project.artifactId}_unitfile_config_timer
     'unit' ? ${project.artifactId}_unitfile_config_unit
 };