Drop Facter 3 and older factsets

[bastelfreak]

Puppet 7 is the oldest supported Puppet version. It vendors Facter 4. The facterdb performance depends on the amount of factsets so it makes sense to get rid of the legacy factsets.

[ekohl]

The main reason I'm in favor of this is faster load times at runtime.

Since we need to update the README as well and do a major version bump, perhaps it's a good time to revisit #262.

[yakatz]

My browser was really unhappy trying to open the diff for this PR :-P
There are a few places in get_facts.sh where puppet6 is mentioned in a comment. It probably wouldn't hurt to change those to the correct strings.

[bastelfreak]

I did a rebase. I'm not sure why some of the tests fail 🤔 someone has an idea?

[yakatz]

I did a rebase. I'm not sure why some of the tests fail 🤔 someone has an idea?

When I change let(:facter_version) { '4.0.0' } to let(:facter_version) { '4.0.52' } which is the version the facts were generated with, it succeeds.

[bastelfreak]

ah lol, yes. Thanks!

[bastelfreak]

IMO this is ready. I ensured that all modern facts are up2date and did a new minor release. I think we can drop the old stuff now.

[TheMeier]

I'm ok with dropping facter 3. Puppet 7 was released over 3 years ago, puppet 6 is EOL for over a year

[binford2k]

I haven't looked at the actual file changes, but in principle I'm in favor of dropping the old versions. They aren't changing, so if people need to use them, they can pin to an older release.