Remove dumpGrepper files

 * Can now be installed with npm i -g dumpgrepper

 * Leaving it out of devDependencies because libxml fails to compile on
   jenkins and there's no optionalDevDependencies in npm, yet.

Change-Id: If21dfcf0575b15776e388e5220d1b6cb811be2f6
Merge "Remove dumpGrepper files"