Remove bootstrap-sass

[jschuler]

And the need for apps to pull in import "@patternfly/quickstarts/dist/quickstarts-bootstrap.min.css";
Create new classes instead that should be bundled into the quickstarts.css.

[rhamilto]

@jschuler, do you know how soon this will be resolved? It is blocking openshift/console#9532, and we intend to deliver that with 4.9 (for which code freeze is in 6 weeks).

cc: @sg00dwin @spadgett