Add a show password SSH-decrypt option

[dmbuil]

Lately I've been playing with the old nova get-password <server> [<private-key>] command, and to my surprise I found out that OSC does implement the feature (yay!). But returns the encrypted version of the key.

As a Quality-of-Life improvement, I thought of implementing an additional --private-key option to allow inline password decryption.

I gave it a try and seems to work:
https://github.com/dmbuil/openstack/tree/feature-server-password-with-privkey

Usage: osc compute server password show [OPTIONS] <SERVER_ID>

Options:
  -h, --help     Print help (see more with '--help')
  -V, --version  Print version

Path parameters:
  <SERVER_ID>  server_id parameter for /v2.1/servers/{server_id}/os-server-password API

Decryption:
      --private-key <PATH>  Path to SSH private key file used to decrypt the password. Supports OpenSSH, PEM RSA, and PKCS#8 formats. If the key is passphrase-protected you will be
                            prompted interactively

I tried not to go against any code-gen directive and preserve the overall spirit of the implementation, but I admit that I am quite a newbie.

[gtema]

That's interesting indeed. The spirit of the code generation tells that we are always capable of creating additional commands (e.g., object-storage container prune) to implement a more complex flows, so we can surely just add a separate command which takes mandatory private key and decrypt the password.
Alternative would be to extend code generation with this case, but this is the only case in the whole Openstack, so it is not appropriate.

All in all, feel free to create a PR with a separate command and we can discuss details there.

Thanks

[dmbuil]

Glad you found it useful! I've created #1817