docs: add getting started guide

[ianna]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.27%. Comparing base (5b18d99) to head (7ce2fd4).

Additional details and impacted files

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##             main      #98   +/-   ##
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  Coverage   75.27%   75.27%           
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  Files           4        4           
  Lines        1630     1630           
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  Hits         1227     1227           
  Misses        403      403           

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[ianna]

@jpivarski and @Moelf - please, have a look at https://juliahep.github.io/AwkwardArray.jl/previews/PR98/. Thanks!

[jpivarski]

It looks great! This can definitely get new users started. If they're familiar with Awkward Array from Python, they might get to the end of the documentation and still be looking for the ak.* equivalents, not realizing that the way they ought to be used in Julia is different: compiled for loops are not something to be avoided. This could, perhaps, be clarified with usage examples, such as a Z peak, with lots of for loops. But a more important first step would be to get physicist users involved. First adopters would figure out what the best practices are, and maybe also find design issues that need to be fixed.

[Moelf]

At some point we probably want to make the documentation entries less redundant, I will see what I can do