rds module: add snapshot capabilities

Add the ability to create snapshots and restore from them
Make instance creation, deletion, restore, and snapshotting idempotent
(really helps testing a playbook if you can run it multiple times)
Merge pull request #5405 from sivel/guide-rax-fix

Rackspace Guide Example Fix
Use a docsite theme that is in source control, work in progress.
Fixing a typo in the Amazon Web Services and Rackspace Cloud guides
Use the sphinx_rtd_theme
Remove static theme files since we're just grabbing the theme from pip.
New Sphinx theme has sidebar navigation so don't need TOC on each page.
Reorg of the documentation tree such that the sidebar will be more correct.  Some work yet to do on module docs.
Fixing a small typo in the Galaxy README template
Split content into subpages.
Add copy of Sphinx RTD theme so we can modify if needed and everyone has a consistent copy.
fix the link formatting
add a link to the resources section
Re-add the playbook introduction which was replaced earlier.
Merge pull request #5416 from sa2ajj/more-minor-doc-fixes

More minor doc fixes
Merge pull request #5414 from jlund/mode-typo

Fixing a typo in the Amazon Web Services and Rackspace Cloud guides
Merge pull request #5415 from jlund/galaxy-readme

Fixing a small typo in the Galaxy README template
shell module: document removes option and sync with command module doc
Fixed syntax error and removed unused imports
Starting to refactor module formatter script.

Rename "jpfunc" to something more explanatory