Refresh README, docs landing page, and scaling plots #4260

Job	Run time
Lint Gate	1m 16s
Detect File Changes	10s
Github (ubuntu, mpi, no-debug, false)	2m 53s
Github (ubuntu, mpi, no-debug, true)	2m 52s
Github (ubuntu, no-mpi, single, no-debug, false)	2m 52s
Github (macos, mpi, debug, false)	2m 59s
Oak Ridge \| Frontier (AMD) (cpu)	2m 39s
Github (macos, mpi, no-debug, false)	1s
Github (ubuntu, mpi, debug, false)	2m 51s
Oak Ridge \| Frontier (gpu-acc)	1s
Georgia Tech \| Phoenix (gpu-acc)	1s
Oak Ridge \| Frontier (gpu-omp)	2m 39s
Github (ubuntu, mpi, debug, true)	2m 51s
Oak Ridge \| Frontier (cpu)	1s
Georgia Tech \| Phoenix (gpu-omp)	1s
Oak Ridge \| Frontier (AMD) (gpu-omp)	1s
Georgia Tech \| Phoenix (cpu)	1s
	24m 9s

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