openssh_keypair - Adding backend option and refactoring backend code

[Ajpantuso]

SUMMARY

Adding backend option to openssh_keypair so that users can select between the OpenSSH binary and cryptography.

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

plugins/modules/openssh_keypair

ADDITIONAL INFORMATION

• Backend code is modeled after other modules in this collection with two backends available to users.
• Some minor changes were made to the naming conventions in the openssh cryptography module_utils and a utility method also used by openssh_cert was brought under the openssh directory to unify the library structure.
• Unit tests were updated to the new names in the module_utils and integration tests were enhanced to 1. move setup_bcrypt to it's own folder and 2. iterate through backends if the installed libraries of the test system are sufficient
• No intentional changes were made to the module's functionality (i.e. no bugfixes), but significant changes were made to the procedural structure, the control flow, and any unnecessary/unused variables/parameters
• Some cleanup to rationalize try blocks and use targeted exceptions was performed while also keeping calls to fail_json within the backend and having a single call to exit_json in the module main method
• Otherwise names were updated for improved readability for example self.fingerprint always contains the SHA256 fingerprint rather than sometimes the fingerprint and sometimes the full output of ssh-keygen -lf FILE

[felixfontein]

Thanks for this PR! Some first quick comments:

[felixfontein]

Looks good! I only have a few smaller comments :)

[felixfontein]

LGTM!

[felixfontein]

@Ajpantuso do you want to add more things, or should I just merge this?

[Ajpantuso]

@Ajpantuso do you want to add more things, or should I just merge this?

Nothing more for now. Additional choices for private_key_format will be added in a future PR.

[felixfontein]

@Ajpantuso thanks a lot for improving this module!

[Andersson007]

@Ajpantuso thank you for the great contribution!