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.

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(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