Add new toy data set and refactor tiltPlot package

[lindadelacombaz]

Closes #86. Dear @maurolepore,

I have modified the toy data set to adapt it to the one from tiltToyData. We agreed with @AnneSchoenauer that I just change the columns' names for now, hence the content remain almost the same. Here is the toy data set from Google Sheet that I have used.

I have also changed the benchmarks as pointed out from you here.

Once that is merged, I will rewrite the remaining deprecated function called "plot_xctr_financial" in another PR.

Thanks ! :)

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