Added an idp role folder and config file

A role has been created that is designed to handle the downloading and
installation of the shibboleth idp software. Also, a corresponding
config file has been made in the project root.
Fixed an issue where the full path was not given

to the unarchive module, causing it to fail due to not being able to
locate the file to unarchive. Also made the get_url inline to fix a
syntax error.
Added the idp role to the top level playbook.
Added a task to create destination directory

The destination directory for the unarchived file has been created in
advance with the new task.
Changed the dest location of the extracted file

The unarchiving task should now place the file in the /opt/aaf/shibsrc
directory created by a previous task. This should ensure proper
structure.
Added the unzip prerequisite package to install

The package unzip will be installed to allow for unzipping of downloaded
files.
Changed destination folders for download

Changed destination for downloaded files to be placed into. Downloaded
idp files are now placed in /opt/aaf/
Readded missing dollar sign

Fixed an issue with a variable that was not properly called.
Rearranged roles so that unzip installs sooner

Unzip is now installed only through ansible instead of the bootstrap
script.
Merge pull request #20 from ausaccessfed/feature/idp

Added tasks for fetching and extracting shibboleth idp