Move examples out of the main repo to twbs/bootstrap-examples

While examples are phenomenally useful and awesome for folks getting
started with Bootstrap, they don't really shine as well being buried in
the main docs. Moreover, having anything that's not core HTML, CSS, JS,
or documentation in the main repo seems to just get in the way.
Therefore, examples gets its own repo.

Specifically, we're doing the following:

* Deletes all example screenshots
* Deletes example layout
* Deletes example files
* Updates Getting Started docs to include only the template and a link
to the new examples project

All the examples and their history will be preserved in the switch.
Merge branch '3.0.0-wip' into bs3_remove_examples

Conflicts:
	docs/_includes/nav-getting-started.html
	docs/examples/navbar-fixed-top.html
	docs/examples/navbar-static-top.html
	docs/examples/navbar.html
	docs/getting-started.html
link order
remove colophon include because there's only one layout using it now
fix link to grid example
Merge pull request #8511 from twitter/bs3_remove_examples

BS3: Move examples to @twbs/bootstrap-examples