Ansible-deployment

- add ``ansible_user`` to ``group_vars`` by default
- add fetch and checkout of roles during update. this enables branch or tag changing
- add persist command to run ``inventory_writers``
- no longer run ``inventory_writers`` on update and init commands
- fix handling of added files from inventory plugins
- add ``deployment.key`` to deployment repo and inventory

- fix package requirements

- move to semantic versioning
- add local inventory source plugin
- add vault inventory source plugin
- add vault inventory writer plugin
- split up inventory plugins into inventory_sources and inventory_writers
- change inventory file structure to explicitly list all hosts in groups
- fix inventory update to add new vars files to deployment repo
- clear screen before showing diff during update
- display newly added files during update

- Fixed a bug in inventory creation from terraform state files containing multiple instances of resources