added etcresolv usersec and userlimits providers

[ibellinf]

Description

etcresolv.rb provides a similar method to etchosts for the /etc/resolv.conf.
userlimits provides an easier interface for setting the default userlimits.
usersec provides a simple interface for setting the passwd stanza.

Issues Resolved

[List any existing issues this PR resolves]

Check List

• All tests pass. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/TESTING.MD
• New functionality includes testing.
• New functionality has been documented in the README if applicable
• All commits have been signed for the Developer Certificate of Origin. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD

[tas50]

This will need to be rebased and the DCO will need to be signed off before we can merge it.