automate the template regeneration for provided templates for #46

Unfortunately, we need to reload all subdirs (minus the vendor
directory).  The "*" matcher is not very clever and cannot be
coerced to match sub directories without potentially matching any
directories longer than their name, e.g. "Sample*" vs "Sample2".

Problem is when these are installed and the templates are wrongly
regenerated.  In theory this doesn't have any bad side effects,
but it may be a potential pitfall to avoid now rather than later.

Mk/plugins.mk

@@ -124,6 +124,13 @@ scripts-auto:
 			    ${DESTDIR}/$${SCRIPT}; \
 		done; \
 	fi
+	@if [ -d ${.CURDIR}/src/opnsense/service/templates ]; then \
+		for FILE in $$(cd ${.CURDIR}/src/opnsense/service/templates && \
+		    find -s . -mindepth 2 -type d); do \
+			echo "/usr/local/sbin/configctl template reload $${FILE#./}" >> \
+			    ${DESTDIR}/+POST_INSTALL; \
+		done; \
+	fi
 
 install: check
 	@mkdir -p ${DESTDIR}${LOCALBASE}