add import statements on at least one example of every operation; cha…

[mkinney]

…nge the docs for Centos; update linux versions; remove Choco facts/operations as it is Windows

• [x] Pull request is based on the default branch (3.x at this time)
• [x] Pull request includes tests for any new/updated operations/facts
• [x] Pull request includes documentation for any new/updated operations/facts
• [x] Tests pass (see scripts/dev-test.sh)
• [x] Type checking & code style passes (see scripts/dev-lint.sh)