Deploy Hooks: use task files

[swalkinshaw]

This implements proper hook files with Ansible tasks as discussed in #305.

This feature is heavily borrowed/stolen from https://github.com/f500/ansible-project_deploy with a few differences.

This PR separates outs the main.yml tasks file into multiple files. Each file represents a "step" in the deploy flow. And for each step we have before and after hooks available.

The steps are:

1. initialize
2. update
3. prepare
4. build
5. share
6. finalize

Also note that technically the after hook of one step and the before hook of the following step are the same. However I wanted to include the before/after nomenclature for semantic reasons mostly. Also so it's more obvious when the hook is run. The f500 project uses hooks like project_deploy_hook_on_initialize which, in my opinion, could be a little confusing as to where/when exactly it's happening.

Hooks available:

• deploy_initialize_before
• deploy_initialize_after
• deploy_update_before
• deploy_update_after
• deploy_prepare_before
• deploy_prepare_after
• deploy_build_before
• deploy_build_after
• deploy_share_before
• deploy_share_after
• deploy_finalize_before
• deploy_finalize_after

Those are all variables which can be defined to override the default. Right now only deploy_build_after and deploy_finalize_after have corresponding hook files to replicate functionality we previously had in the commands.

[swalkinshaw]

Original: #320