Official code documentation is hard to find

[JohannesPertl]

The link to the official documentation for NS is only located in the Scripts Editor ingame.
This is confusing for new users, as it should also be included in the Documentation page of the sidebar, especially because of the deprecated Beta RTD.

Suggestions:

• Add the link to the Resources section of the ingame Documentation page
• Add the link to the main README.md
• Add a disclaimer that https://bitburner-beta.readthedocs.io/en/latest/index.html is deprecated, as it is the first result on google

[catloversg]

Most of your suggestions were implemented on the dev branch. Updating README.md will be handled by #1697.