benchmarks: Hide data/ folder

[homersimpsons]

The data/ folder contains raw data.

It should not be displayed in the tabs, and its *.cbor files should not be rendered

Implementation:

• Previously we were listing the directory names to use
• Now I'm listing criterion/<directory>

Alternatively I can continue listing the directory names, but then I should exclude the .cbor files, which will lead to far more false-positive files.

Fixes #66

This Pull Request was made possible thanks to #67 (thanks @olivierlemasle)

• I do not like liquid template engine, it feels like so much things are missing (using | split: ", " to create an array ?!, error with concat on line 29 while there is no concat on this line ?!, I used an inexistant spit filter and the engine did not report it to me ?!)
• feel free to discuss the changes
• looks like we are not using version 5 so I cannot use liquid tag https://shopify.github.io/liquid/tags/template/#liquid

[youknowone]

Thank you!