Names of quickstarts are wrong

We should use consistent names for quickstarts in all locations, which are governed by the quickstarts themselves:

• Hello World -> helloworld
• Hello World JMS -> helloworld-jms
• Hello World Errai -> helloworld-errai
• Hello World OSGi -> remove it entirely
• Kitchensink -> kitchensink
• Number Guess -> numberguess
• Aerogear HTML5/Mobile -> kitchensink-html5-mobile
• Greeter -> greeter