clean up CTest infrastructure

[BenWibking]

Describe the proposal
We can follow what WarpX does and streamline the CTest testing infrastructure: ECP-WarpX/WarpX#5068.

We can also use CTest for nightly regression testing, if we use WarpX-style checksums for each output variable (i.e., the sum over all cells in each multifab. This turns out to be a sensitive test of whether the contents of the output are actually the same or not.). Then we don't have to store benchmark solutions that take up a lot of disk space.

Describe alternatives you've considered
N/A

Additional context
We duplicate a lot of things in each CMakeLists.txt for each problem/test.