Add new API to add ssh key to a specific user

[dilshat]

We need to provide method to add an ssh key to authorized keys file of a specified user inside a container

[akarasulu]

What are the existing API's?
What are their signatures, and semantics?
Who calls them and who executes them?

[dilshat]

SshKeys io.subutai.common.peer.Peer#readOrCreateSshKeysForEnvironment - creates ssh keys inside all containers and returns them to caller

io.subutai.common.peer.Peer#configureSshInEnvironment( EnvironmentId environmentId, SshKeys sshKeys )
adds specified ssh keys to all containers within environment

io.subutai.common.peer.Peer#addToAuthorizedKeys( EnvironmentId environmentId, String sshPublicKey ) adds a specified ssh key to all containers within environment

these methods are called by Bazaar module (or environment manager in case of local environments) during environment build

[samsonbek]

adds specified ssh keys to all containers within environment

we need API to add ssh keys only to several chosen containers.

[dilshat]

Check user existence id -u {username}
Create user with home directory useradd -m {username}