Find package wrapper

[zachcran]

Description

This PR utilizes the find_package wrappers added by NWChemEx/NWXCMake#59.

TODOs

• Verify that it works when built independently
• 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

[zachcran]

Checks can't pass until NWChemEx/NWXCMake#59 is merged.

[jwaldrop107]

LGTM

[zachcran]

@jwaldrop107 @ryanmrichard All unit tests are passing now after the fix in NWChemEx/NWXCMake#60! This is ready for final approvals.