Add in all builting plugins [extrinsic, filetype, image_stats] with comments

on utility.  All but extrinsic commented out and can be activated by uncommenting.

src/data/plugins.txt

 bdqc.builtin.extrinsic
-bdqc.builtin.tabular
+
+# most plugins are dependent on extrinsic
+# uncomment or comment plugin lines to activate or deactivate
+
+# tabular data
+#bdqc.builtin.tabular
+
+# image data
+#bdqc.builtin.image_info.image_stats
+
+# determine and record filetypes
+#bdqc.filetype