This PR updates some old information on the documentation.
Updating installation instructions for XBlocks on the Docker Devstack
Removing references of the color bar for indicating status on sections (the color bars are now only on the subsections)
[ ] @viadanna
[ ] Doc team review (sanity check, copy edit, or dev edit?): @edx/doc
[ ] EdX Expert TBD
[x] Ran ./run_tests.sh without warnings or errors
[ ] Add a comment with the description of this change or link this PR to the next release notes task.
[ ] Squash commits