Reorganize reform related files

We currently have most of the reform related variables in the `reforms` folder, however some file have in the `variables/contrib` folder, we should add all of the variables to the `reforms` folder

In the tests folder, all reform related files should be organized in `policy/contrib` while but some files now are organized in `policy/baseline/contrib`

Compare the reform-related files under reforms and variables/contrib, then review the corresponding files in tests/policy/contrib and tests/policy/baseline/contrib. Move the variables and tests into the requested folders, preserving their contents, and confirm that the test suite still passes with no references to the old locations.

Written by the indexing model from the issue text.