Add more detailed documentation on Artifacts

[mlodic]

As of now the Artifacts section in the doc is quite lean. See: https://intelowlproject.github.io/docs/IntelOwl/usage/#analyzables-artifacts

We should add documentation about:

• how to add a new artifact: explain where it is possible to do that, how basic/advanced evaluations work, how decay works, and so on.

It is important to do and share in the doc all possible screenshots from the app that can help the understanding.

[sristyanand00]

Hi @mlodic ,

I'd like to work on this! I can add detailed docs explaining how Artifacts work in validations, with examples and screenshots. Please assign it to me?