Remove installation script

[paulfantom]

Replacing installation script with ansible tasks along with some more cleanup.

Installation method based on previous script and official docs (https://docs.docker.com/install)

Added:

• easier upgrade method (just specify latest as docker_version)
• testing on latest version
• tasks/configure.yml file for cleaner look

Removed:

• installation script and everything connected with it
• unused files
• some simple templates
• docker_upgrade and upgrade_docker variables. Backwards compatibility is maintained by setting docker_version: latest when any one of those two vars is detected (not checking value)

Resolves #31

[paulfantom]

After finishing it, I can start work towards #33.

[paulfantom]

@mongrelion I think this is ready.

[paulfantom]

After merging this I think I could provide a publicly accessible "live" demo usage of this role, by using it here instead of current one.

This site is deployed daily and have nice interface for analysis.

[mongrelion]

It's a big change but it's looking good. One thing I noticed, though, is that we don't make sure after installation that Docker is properly running. I'm creating a separate issue for that.

As per the demo, it sounds good to me. Create a separate issue for that and make sure to add a link to the demo on the README :)

[paulfantom]

Do we really need to check if it is running? There is this handler: https://github.com/mongrelion/ansible-role-docker/blob/master/handlers/main.yml#L2 also we are having unit tests for this here: https://github.com/mongrelion/ansible-role-docker/blob/master/tests/test_default.py#L37

I think that enabling this: https://github.com/mongrelion/ansible-role-docker/blob/master/tests/test_default.py#L33 would solve most cases