Improve Pan language support (#3691)

* Add a larger set of sample files for Pan

This is a fairly good cross section of Pan based on code from:
* https://github.com/quattor/template-library-examples
* https://github.com/quattor/template-library-core

* Add Pan language grammar

samples/Pan/simple.pan

@@ -0,0 +1,20 @@
+unique template site/ceph/osdlocal/simple;
+
+variable CEPH_JOURNAL_PART ?= dict();
+
+prefix '/software/components/ceph';
+
+'localdaemons/osds' = {
+    d = dict();
+    foreach(idx; osdmnt; value('/system/filesystems')) {
+        part = osdmnt['block_device'];
+        disk = replace('\S+/([a-zA-Z]+)[0-9]*$', '$1', part);
+        if (match(osdmnt['mountpoint'], '/var/lib/ceph/osd/\w+')){
+            d[escape(osdmnt['mountpoint'])] = dict(
+                'journal_path', format('/dev/%s%d', disk, CEPH_JOURNAL_PART['data']),
+                'crush_weight', weight_of(part),
+            );
+        };
+    };
+    d;
+};