User interfaces documentation

Add description for Web UI and RockStor setup process
Add setup process image
documentation for user interfaces

Add description for cli
Add screenshot for cli
User administration

Add documentation for create and edit user
Add images for create and edit user
Services documentation
Dashboard documentation

Add documentation and images for dashboard and widgets
Add network widget image to dashboard documentation
Update dashboard, users, services documentation
Documentation

Add documentation for ldap, nis and ntp configuration
Add images for ldap, nis and ntp configuration
Add screenshot for ad configuration
general modifications
general modifications to users doc
changed On to In
minor changes user interfaces and services documentation
Merge pull request #12 from sujeetsr/issue#3_user_interfaces

Issue#3 user interfaces