remove unused configs; clean up CI pipeline

[juliasloan25]

Purpose

This PR does a few things:

• remove unused config files
• remove outdated jobs from CI
• remove redundant/unnecessary jobs from CI
• unify config file naming
• organize CI pipeline into clear slabplanet/AMIP sections; move hierarchy experiments to end

The regular pipeline now includes:

• MPI and GPU unit tests
• 14 slabplanet experiments (10 on CPU, 4 on GPU)
• 11 AMIP experiments(6 on CPU, 5 on GPU)
• hierarchy test cases

closes #1080

Content

• remove unused configs
• remove unnecessary simulations from regular CI pipeline
• organize CI pipeline: clear slabplanet and AMIP experiment sections
• update README to use example of config we still have
• remove "gpu_" prefix, "single"/"mpi" from config names (architecture/hardware is separate from simulation setup)
• remove "target_" prefix from config names (targets have changed)

Jobs removed from CI pipeline

• Slabplanet: albedo from static map
  • static map albedo is already used in default case
• Moist earth with slab surface - default: monin gray no_sponge idealinsol freq_dt_cpl
  • uses "default_mono" config: very similar to default slabplanet but naming is more confusing
  • only difference is diagnostics
• Moist earth with slab surface - notmono: monin gray no_sponge idealinsol freq_dt_cpl notion
  • uses "default_notmono" config: very similar to default slabplanet nonmono but naming is more confusing
  • only difference is diagnostics
• Moist earth with slab surface - test: bulk allsky sponge realinsol infreq_dt_cpl
  • target_params_in_slab_test2 config is identical to target_params_in_slab_test3
• AMIP - Float64 test
  • Float64 already tested as default
  • very similar to more complex setups, e.g. "AMIP - Float64 + hourly checkpoint"
• "gpu_amip_albedo_function.yml" config
  • lower-resolution version of "target_amip_albedo_function.yml", which is now run on both CPU on GPU and renamed to "amip_albedo_function.yml"

Naming changes

• run "Moist earth with slab surface - test: bulk allsky sponge realinsol infreq_dt_cpl" renamed to "Slabplantet: timevarying insolation + rayleigh sponge"
• config renamed: "coarse_mpi_n4.yml" -> "amip_coarse_mpi.yml"
• config renamed: "coarse_single_ft32" -> "amip_coarse_ft32.yml"
• config renamed: "coarse_single_ft64_hourly_checkpoints" -> "amip_coarse_ft64_hourly_checkpoints"
• config renamed: "coarse_single_ft64_hourly_checkpoints_restart" -> "amip_coarse_ft64_hourly_checkpoints_restart"
• all "target_amip_..." configs renamed to "amip_..."
• all "gpu_amip_..." configs renamed to "amip_..."
• config renamed: "gpu_amip_albedo_static_map" -> "amip_default" (static map is default albedo type)