add GPU AMIP scaling runs

[juliasloan25]

ClimaAtmos has scaling runs for the "aquaplanet chap" setup introduced in CliMA/ClimaAtmos.jl#2724. These use 1, 2, and 4 GPUs each, and all run with MPI. We should setup analogous runs in ClimaCoupler using the same atmos setup/config files.

note: atmos prints SYPD at end of simulation. We'll need this too to plot SYPD vs # GPUs

This also requires setting up a new buildkite pipeline for coupler performance testing, analogous to ClimaAtmos' Target GPU Simulations pipeline. This pipeline will be triggered manually when we want to do performance testing, unlike the automated shortrun and longrun pipelines. I've set it up here: https://buildkite.com/clima/climacoupler-target-gpu-simulations

part of #390

[juliasloan25]

This pipeline (now at https://buildkite.com/clima/climacoupler-cpu-gpu-benchmarks) is being used for our benchmark runs. We decided that right now it's more useful to test the performance of different configurations, rather than to test the performance across architectures every week. We can manually run scaling tests as needed, or add a new pipeline for them if we decide that will be helpful