generate ssh keys for provided users

Description

Action for the ssh keys generation.

Proposal

ssh_keys:
  - user: "tziol"
    bits: 2048
  - user: "bdaca"

Action should create key with optionally specified number od bits for user if:

• the user exists
• the key was not created before

Action will NOT overwrite existing key even if the number of bits differs.

Links / references

• user module to generate ssh key