Switch to SSH key value passthrough for Azure and harmonize approach with AWS

What does this MR do?

MR switches to a more coherent design for SSH Key setup on Azure by making it value based.

This allows for more flexibility for users to pass in the SSH Key value from any source (such as from secrets lookups) instead of requiring it to be a filepath.

MR adjusts AWS params to be named the same for consistency.

Params for Azure and AWS are deprecated with this change but will continue to work until the next major release (3.0.0).

Related issues

Closes #412 (closed)

Author's checklist

When ready for review, the Author applies the workflowready for review label and mention @gl-quality/get-maintainers:

• Merge request:
  • Corresponding Issue raised and reviewed by the GET maintainers team.
  • Merge Request Title and Description are up to date, accurate, and descriptive
  • MR targeting the appropriate branch
  • MR has a green pipeline
  • MR has no new security alerts in the widget from the Secret Detection and IaC Scan (SAST) jobs.
• Code:
  • Check the area changed works as expected. Consider testing it in different environment sizes (1k,3k,10k,etc.).
  • Documentation created/updated in the same MR.
  • If this MR adds an optional configuration - check that all permutations continue to work.
  • For Terraform changes: setup a previous version environment, then run a terraform plan with your new changes and ensure nothing will be destroyed. If anything will be destroyed and this can't be avoided please add a comment to the current MR.
• Create any follow-up issue(s) to support the new feature across other supported cloud providers or advanced configurations. Create 1 issue for each provider/configuration. Contact the Quality Enablement team if unsure.