Join hooks from all paths

Due to inigrep limitation, we cannot automatically cherry-pick hook.ini
based on where the hook is found--we can only have all hooks in one
file, or use join strategy.

src/bin/saturnin.skel

 }
 
 run_hook() {
-    saturnin conf -p hook.$SATURNIN_SUBCOMMAND.$1 \
+    saturnin conf -j -p hook.$SATURNIN_SUBCOMMAND.$1 \
       | debug_pipe hook_$1 \
       | bash
 }