Revert #12461 -- add salt_data kwarg instead
Revert #12461 -- add salt_data kwarg instead

After testing by @jasonrm the previous refactor in 1525f211 didn't quite
work as expected, so I've reverted those changes and instead have added
a new kwarg to the render function that will control if the function
returns salt data or the composed scope for reuse elsewhere.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt