Add identified distro and version to output for JSON presenter

[zhill]

What would you like to be added:
Add identified distro and version to the JSON output at least, and optionally the text output as well for docker:// analyzed images.

Why is this needed:
Identification of the distro is useful for other downstream consumers of the syft SBoM for correlating with other dbs or making decisions on acceptability if distro control is important to the user.