CI/CD: automatic VirusTotal scan

[nopeitsnothing]

Please describe the scope.

Adds GH action to automatically scan the guide[.pdf|.odt].

Note: New release files will have an updated hash and thus a new VT scan URL.

Pay attention to these hash changes using the Howto verify page on our website.

Please describe the solution.

This GH action will be permanent.

Please see the latest scan results here:

1. guide.pdf: 52ae8a7411f826d6b04c5b817bf8cbed0f99957e6a910bcc88065a9a61233af1 - complete scan
2. guide.odt: 390f23ab975488a53135dfe61f66b54393a4bd85bded3a8a5c052975969bb947 - complete scan

Please describe alternatives.

N/A

Give any additional relevant context.

N?A