add cloudbridge python provisioning to airavata cloud module

[gouravshenoy]

PR contains the following changes to the cloud module:

1. EC2 instance provisioning code using Cloudbridge python library.
2. Ansible script to provision instances in OpenStack based cloud.

Here are some details of all changes made:

• Added new Python code, which uses Cloudbridge library, to provision instances on EC2. Some of the current functionalities include:
  a. Create new instance on EC2 (using credentials stored in a yaml file)
  b. Delete an instance on EC2.
  c. Get a list of instances running on EC2.
• The existing "modules/cloud/cloud-provisioning" directory, which was a java project containing code to provision OpenStack instances, has been made as a parent folder with the following 2 sub-directories:
  a. java-provisioning (moved the existing java project under this)
  b. python-provisioning (added new python code for ec2 provisioning under this)
• This python module can be extended to handle provisioning on other cloud providers (eg: OpenStack) by implementing the "CloudInterface.py" python interface. I plan on adding OpenStack provisioning soon.
• Added ansible script to provision multiple instances in OpenStack based cloud. These provisioned instances can then be used to deploy a mesos-marathon cluster on top of them using mesos deployment script. This is in addition to Shameera's existing script for EC2 provisioning.

[lahirug]

@gouravshenoy I think this patch need more description what you did, diff have 50 files changed, 1746 insertions(+), 1297 deletions(-).

[gouravshenoy]

@lahirug : Thanks for the comment. I have updated the description to list more details.

[gouravshenoy]

Added new ansible script to the cloud-module. The pull-request has been updated with this code, and I have also updated the description of the PR.