[Feat] Create GRASS cheat sheet

[petrasovaa]

I think GRASS could benefit from a cheat sheet. We could have a general one for beginners, and also maybe more focused on raster/vector/temporal processing. I imagine it could have a poster format with commands and simple figures.

Something like this:
https://pandas.pydata.org/Pandas_Cheat_Sheet.pdf

Some possible items could include e.g. region handling, how to find a get help (g.manual, --help), raster/vector import. Feel free to propose ideas below.

[lucadelu]

I would like to contribute, I found some possible latex template/source code to adapt for our cases

• http://tug.ctan.org/info/latex-refsheet/LaTeX_RefSheet.tex (http://tug.ctan.org/info/latex-refsheet/LaTeX_RefSheet.pdf)
• https://www.latextemplates.com/template/cheatsheet
• http://wch.github.io/latexsheet/

[veroandreo]

The idea is very nice indeed!

Let's make it eye-catching with diagrams and example figures here and there. Also, we should pick a grass-y color palette.

For the temporal part, I can offer this diagram in case it's useful (I must have the svg somewhere)

(sorry for label removal, was unintentional...)