Add ssh key input for users during users creation.
add low level helper code to add ssh pub key for a user.
Merge branch 'master' into Mchakravartula-issue#463_add_optional_ssh_keys_for_userCreation
Update user model to store ssh pub key.
Update user api to support ssh pub key.
save public key during post.
Display the SSH key if exists when user try to edit user.
Merge branch 'issue#463_add_optional_ssh_keys_for_userCreation' of github.com:Mchakravartula/rockstor-core into issue#463_add_optional_ssh_keys_for_userCreation
Merge branch 'Mchakravartula-issue#463_add_optional_ssh_keys_for_userCreation'