Docs overhaul!

[kmdeck]

• [x] restructuring repo PR #254
• [x] tutorial: canopy model tutorials (standalone, coupled with hydrology) PR #258
• [ ] check links in docs to make sure they are still correct PR #256
• [ ] remove warnonly flag so tests fail if docs are incorrect #357
• [x] standalone docs PR #214
• [ ] driver tutorial #439
• [ ] integrated docs: think of what info would be important...
• list of the standalone models integrated (?)
• list of aux (p) and prognostic (Y) variables, with units (?)
• recommended timestepper and resolution (?)
• ...
• [ ] tutorial: canopy+soil to be for the full soil model
• [ ] tutorial: implicit tendencies, setting up IMEX problems
• [ ] review current docs to make sure mistakes havent crept in
• [ ] ClimaLSM interactive run inside the docs (via server)