Removes outdated gulp setup helper

src/Umbraco.Web.UI.Client/setupgulp.bat

@@ -1,22 +0,0 @@
-@ECHO OFF
-
-ECHO.
-ECHO.
-ECHO This will only work when you have NPM available on the command line
-ECHO Works great with NodeJS Portable - https://gareth.flowers/nodejs-portable/
-ECHO.
-ECHO.
-set /P c=Are you sure you want to continue [Y/N]?
-if /I "%c%" EQU "Y" goto :setupgulp
-if /I "%c%" EQU "N" goto :eof
-
-:setupgulp
-call npm install
-call npm -g install gulp
-call npm -g install gulp-cli
-
-ECHO.
-ECHO.
-ECHO You should now be able to run: gulp build or gulp dev
-ECHO.
-ECHO.