O5.4.3 Audit and remove easy-to-remove dependencies

[juliasloan25]

We may have some packages being used in ClimaCoupler.jl that we don't need anymore, or that we can easily implement workarounds for. We need to first identify these packages, and then remove them. We can start a list in this issue of any such packages.

Tasks

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1. Identify and document removable dependencies #1075
   Dependencies 🔗 enhancement +2
   
2. Remove dependencies
3. Remove Plots.jl dependency #1091
   Dependencies 🔗 enhancement +2
   
4. remove easily-removable files in experiments/ClimaEarth/ #1067
   enhancement +1
   
5. reduce number of Julia environments #1056
   💰 Grab Bag +1
   
6. remove perf/ folder #1057
   💰 Grab Bag enhancement +2
   
7. move imports out of driver, into file they're used in #1101
   🍃 leaf 💰 Grab Bag +2