Find package wrapper

## Description This PR utilizes the `find_package` wrappers added by NWChemEx/NWXCMake#59. ## TODOs - [x] Verify that it works when built independently - [x] Verify that it works when built in Spack ## NOTE Original PR description below, when the wrappers were implemented here. --- (Moved to NWChemEx/NWXCMake#59) ## Is this pull request associated with an issue(s)? None that I could find. ## Description This adds wrapper functions to CMake's `find_package()` that add a wrapper target in CMaize. This allows them to be added properly as dependencies for the main project target and appear properly in the installed `<package>Config.cmake` and `<target>-target.cmake` files. ## TODOs - [ ] Potentially rename the added functions to avoid implying that they are in the CMaize package (or migrate them to the CMaize package) - [ ] License header? - [ ] Validation of pairwise TARGETS argument to `cmaize_find_package` - [ ] Removed leftover commented-out code - [ ] Add function-level documentation