Fixes Issue 125 - Hanlon client config contains unnecessary parameters

After separating Hanlon into cli and web components, we created hanlon_client.conf to manage client side configuration parameters. Most of the parameter belonging server side logic are removed from client config except for image_path and persist_xxxx set. Client code models were using parameter due to entangled code where client is implementing the code logic or server and client code blocks are placed in single file. To remove these parameters we needed another code refactor which is addressed in this pull request.

This pull request completely removes the above said parameters by...
*. Removing db interfaces where not required and isolating the dbinit to server line of code execution
*. Removing cli/hanlon config db_check command which is not required at client end
*. Moving local image path building logic from client end to server
*. Extending hanlon image rest api end point by adding local_image_path parameter

I'm not sure we should change this from `line_number` to `serial_number`, @sankarvema, since this field represents the line number of the policy in the policy table.  Personally I'd rather continue to call this field `line_number` (and create an accessor using a command like `attr_accessor :line_number` instead of the `attr_accessor :serial_number` command shown in line 25, above). Of course, if there are others who feel strongly that serial_number is a better name for this field, let me know...I could be convinced otherwise.