Refactor old uses of command module

[Jyrsa]

A lot of the playbook uses command module to do things for which there has always been an ansible-native way (particularly the file module) or for which a new module has been made since the writing of these roles.

The ansible modules are more robust against unforeseen circumstances.

[Jyrsa]

Essentially this is about going through the tasks that use command to check if a git module exists.

Should be left until we're running 2.3 which will have modules for creating OpenSSL public and private keys and temporary directories.