feat: initialize command for cac to oscal transformation

[qduanmu]

Description

Initialize a command for data transformation from CaC content to OSCAL

Fixes CPLYTM-424

Type of change

• New feature (non-breaking change which adds functionality)

How has this been tested?

$ trestlebot sync-cac-content --help
...
  --cac-content-root TEXT         Root of the CaC content project.  [required]
  --product TEXT                  Product to build OSCAL component definition
                                  with  [required]
  --cac-profile TEXT                  Control to use as the source for control
                                  responses  [required]
  --oscal-profile TEXT                  Main profile href, or name of the profile in
                                  trestle workspace  [required]
  --component-definition-type [service|validation]
                                  Type of component definition

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
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[huiwangredhat]

LGTM. I compared the options with the options in build_cd_from_policy.py, the output would be using the git repo repo-root/component-definitions to store.