provisioner: merge galaxy config into common

[nywilken]

The Ansible galaxy arguments for both provisioners were duplicated among the provisioners although they are essentially the same. Since they're the same, we move the common code and arguments into a common package so it can be reused between both provisioners.

[nywilken]

@SwampDragons this is where I got to on the refactor. Sharing in case you find anything usable.

[SwampDragons]

Thanks. I'll take a look at it when I have some downtime.

[hashicorp-cla]

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