Update role using community.crypto

[leophys]

Hi! Thank you for this role!
I update it using the ansible community.crypto collection. The logic should be the same and in the original spirit of the role you wrote. I just changed minor things:

• added an (optional) task to populate the /etc/hosts file with the nodes in the inventory
• added a Vagrantfile to test this role locally
• made so that the certificates are copied to the remote machines in a configurable path that defaults to /etc/ssl/local/{certs,private}
• changed all the variables name to have a pseudo-namespace gen_tls_, to ease the use of this role together with others

Let me know what you think of it.