Automate Passwordless SSH during each omnia.yml execution

[sakshiarora13]

Is your feature request related to a problem? Please describe.
At present, after omnia.yml execution from AWX, user needs to run passwordless_ssh.yml to setup passwordless SSH within the cluster.
If user adds any new node in the cluster and wants to setup passwordless SSH for this new node, He'll have to execute passwordless_ssh.yml template again from AWX.

Describe the solution you'd like
We have 2 scenarios where omnia.yml can be executed, i.e, from command-line and from AWX.
We support passwordless_ssh.yml template only from AWX.
Thus, a check can be created to verify if omnia.yml is being executed from AWX. If it is, then passwordless SSH playbook is included, else skipped.