Drop Scaffolding sample page.

It has no Wicket related demos.
It is outdated (some things are about Bootstrap v2).
These docs should better be maintained by Bootstrap itself because it is hard to keep it up-to-date here.
Merge pull request #471 from l0rdn1kk0n/drop-scaffolding-sample-page

Drop Scaffolding sample page.
Merge branch 'master' into wicket-7.0.0-M1