Add documentation on x11vnc
put all of the setup steps in dependencies.post
try to explain motivation for sharing the X server
Tree-shaped artifacts list UI
Tree-shaped artifacts list UI
Merge pull request #3543 from circleci/update-vnc-doc

Update vnc doc
Merge commit 'f8ab072e83b843dbac00a9221cf82440a737298d'
Merge commit 'cfb9982a3688fefb868097153d7f5ac1f07e559d'