Move the FactsImageOptions from distro to the new rhsm/facts package.
At the same time define the values we use as an enum, including the
"test-manifest" value.
Though the values don't really matter, the test value is defined first
so it takes the 0 value, which feels nicer conceptually.
The field in the distro.ImageOptions is changed to be a pointer to allow
for nil values.
ffa1e1df17