feat(validation): #217 handle multi model validation (not delimited)

[mike-winberry]

Description

217

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Other (security config, docs update, etc)

Checklist before merging

• [ ] Test, docs, adr added or updated as needed
• [ ] Contributor Guide Steps followed

[mike-winberry]

@CloudBeard Should be enough there to see what changes or additional functionality you might want.

@defenseunicorns/lula-dev Not sure about the validate command integration yet would like some feedback prior to implementing, current thoughts:

• for go-oscal validate single model should be the default? (since oneOf is the expected schema state)
  • flag? for multi
  • agnostic, handle based on file contents (assumes user intent)

[mike-winberry]

Closing as it is no longer relevant.