Fail better in ansible provider when provided non-ansible code

[tas50]

Describe the bug
Today if you try to scan YAML that's not necessary a playbook the provider throws unmarshall errors. We should validate the code to some degree and throw a friendly error message if we can't parse the code.

Example where I scan defaults/main.yml from our ansible role:

cnspec scan ansible main.yml
→ found a new version for 'ansible' provider installed=10.0.0 latest=11.0.0
→ successfully installed ansible provider path=/Users/tsmith/.config/mondoo/providers/ansible version=11.0.0
→ loaded configuration from /Users/tsmith/.config/mondoo/mondoo.yml using source default
→ using service account credentials
→ discover related assets for 1 asset(s)
x unable to create runtime for asset error="rpc error: code = Unknown desc = yaml: unmarshal errors:\n  line 7: cannot unmarshal !!map into play.Playbook" asset=
Asset:
-------

error: rpc error: code = Unknown desc = yaml: unmarshal errors:
  line 7: cannot unmarshal !!map into play.Playbook