Add ability to install rbenv independently

- Can now install rbenv separately. Can be used as a requirement in a
  state for installing rbenv plugins using the git or file states
Fix description of method and whitespace lost
Add event function to state runner for light event interaction via CLI
Merge pull request #11067 from gravyboat/develop

Update to cmd state documentation for a note on creates.
Add survey to runner index
Merge pull request #11068 from holmboe/survey-runner-index

Add survey to runner index
Compare to `None` instead.

Which is what's returned by `salt.utils.which` in case the binary is not
found.
Update doc to reflect proper `__virtual__` usage.
Show how to use `__virtualname__`
Merge pull request #11069 from s0undt3ch/hotfix/minor

Minor corrections
Fix file.recurse states with trailing slashes in source

Resolves #11002.
salt.cloud.lxc: Optimized salt client
Safebelts for lxc provisionning:

Cloud:
    - Allow to use alternate config prefixes
    - Filter default options

LXC module:
    - Filter default options in create
Report errors when preparation fails

Previously salt daemons could fail to start without giving any
reason, when (for example) chown failed during the startup.
This change doesn't fix anything, but at least reports the error
back to the user.
salt.states.archive: multiple improvments

- add a new keep paramater to optionnaly not delete the archive after extraction
- Fix the traceback in case of tar error by correctly returning a state return mapping
- Correctly handle extra tar options if any by adding defauts ones if only needed
- Pep8
- When silently extracting with tar, be sure that the no output stuff won't be
  handled as a failed extraction.
Merge pull request #11070 from terminalmage/11002

Fix file.recurse states with trailing slashes in source
Add normalize_name function

This will pave the way for .x86_64 architectures to be used in pkg
states.
Normalize package names
Normalize package names
Normalize name for single package target