(0.7.0) Revamp VerticalGrids + add Docs for VerticalGrids

[navidcy]

This is ready for review.

The PR changes the user interface for creating vertical grids.

Also adds a section in the Docs describing the vertical grids. Preview should be here but it might take few hours until you get the final version

https://clima.github.io/ClimaOceanDocumentation/previews/PR565/vertical_grids/

Next should come a PR with a vertical grid implementation that allows us to specify surface spacing, Nz and depth. Will probably involve iterative process, e.g. in the spirit of https://doi.org/10.1016/j.ocemod.2017.03.012

[codecov]

Codecov Report

Attention: Patch coverage is 30.61224% with 34 lines in your changes missing coverage. Please review.

Project coverage is 21.10%. Comparing base (9a01516) to head (80bbe6f).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/GridUtils.jl	27.65%	34 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #565      +/-   ##
==========================================
- Coverage   23.42%   21.10%   -2.33%     
==========================================
  Files          48       48              
  Lines        2869     2886      +17     
==========================================
- Hits          672      609      -63     
- Misses       2197     2277      +80     

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[navidcy]

merge?

[glwagner]

I think "Grid utilities" is a better name than "Vertical grids" now. but this belongs in Oceananigans too

[navidcy]

Merging now.

CliMA/Oceananigans.jl#4623 aims to move ExponentialCoordinate to Oceananigans. When that's merged we can drop it from ClimaOcean.