feat(general): add Azure Pipelines framework

[gruebel]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Description

• added support for scanning azure-pipelines.yml files, which are the main entrypoint for configuring an Azure Pipeline
• added 3 checks
  • Ensure container job uses a non latest version tag
  • Ensure container job uses a version digest
  • Ensure set variable is not marked as a secret
• added docs and hopefully all other minor references, like check docs creation

Future PR:

• support for Image Referencer

Out of scope:

• support for template file references

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my feature, policy, or fix is effective and works
• New and existing tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[tsmithv11]

Looks great! Can you add one non-container policy? For example, setting a secret variable ina. script with logging commands: https://learn.microsoft.com/en-us/azure/devops/pipelines/process/set-secret-variables?view=azure-devops&tabs=yaml%2Cbash#set-secret-variable-in-a-script-with-logging-commands

Some other sources:
https://learn.microsoft.com/en-us/azure/devops/pipelines/security/templates?view=azure-devops
https://learn.microsoft.com/en-us/azure/devops/pipelines/security/misc?view=azure-devops