Ease application configuration

[pacoorozco]

Is your feature request related to a problem? Please describe.
There are a lot of settings to configure in this applications. Most of them should use defaults and calculated values.

Describe the solution you'd like

• Instead of submitting private & public keys, user should be able to create or submit a private key. The public key could be created from the private one.
• Users should set a writable folder on the remote hosts when SSHAM can deploy ssham_file, non_ssham_file, cmd_remote_updater. E.g. ~/.ssh/ssham
• Remove unused temp_dir setting.
• Hybrid mode will configure the cmd_remote_updater using field cofigured in 2

[pacoorozco]

Points 2 and 4 are not implemented. With the current implementation the SSHAM could be customized, otherwise we should hardcode our assumptions.