Update README.md for quickstarts to reflect new location?

[kb1ca]

It looks like there is work underway to migrate quickstarts out of https://github.com/fabric8io/ipaas-quickstarts/tree/master/quickstart/ and into https://github.com/fabric8-quickstarts/.

Unfortunately, the docs still link to the original location and README.md doesn't guide readers to the new location, giving the impression that the quickstarts are broken and/or incomplete.