Whitepaper: footnotes & formatting improvements

[nikolaev-rd]

• footnotes — formatted via <sup>[7]</sup>:

  some text^[7]

• captions for images / tables — italic font, not quote
• added indentation for images in lists

[kenfinnigan]

@nikolaev-rd could you please sign the DCO for your commit to be mergeable? Thanks

[nikolaev-rd]

@kenfinnigan review please

[netlify[bot]]

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[alolita]

@bwplotka can you please review this PR for the whitepaper? Else please close if out of date.