docs: AVNU, Pragma and Snapshot X audits

[milancermak]

Adding audit reports of AVNU, Pragma and Snapshot X.

Checklist

• The URL is not already present in the list (check with CTRL/CMD+F in the
  raw markdown file).
• Each description starts with an uppercase character and ends with a
  period.
  Example: cairo - The Cairo programming language.
• Drop all A / An prefixes at the start of the description.

[milancermak]

Test fails on a thing I didn't touch 🤷

[robertkodra]

Nice, I saw that Avnu is missing, could you add that as well on this PR? @milancermak

https://github.com/NethermindEth/PublicAuditReports/blob/main/NM0141-FINAL_AVNU.pdf

[milancermak]

Oooh, I missed AVNU's report. Thanks, will add (and read 🤓 ).

[amanusk]

Thank you for the great additions!