Adjust the Louisiana school readiness tax credit to match model standards

Current issues:
- not included in the net income tree

- refundable and non refundable credits are summarized in one file credit variable; should be kept separate

- variable file name does not match class

Start by locating the Louisiana school readiness tax credit implementation and the net income tree. Compare the current refundable and nonrefundable credit handling and the variable filename with its class name; done means the credit is included in the net income tree, the credit types remain separate, and naming matches.

Written by the indexing model from the issue text.