More complex detection condition logic

[AMDmi3]

For now, we only support OR logic for detection conditions. We may need AND logic as in "opsys=Linux AND /etc/gentoo-release file present". From syntax standpoint, either simple detection-and: alternative to detection:, or nested constructs as in

detection:
  - and
    - file-in-etc: gentoo-release
    - or
      - opsys: Linux
      - uname-s: Linux