docs: SSH documentation in README and change to web page

[Prodeguerriero]

Hi there!

I hope I am not overstepping any boundaries here. 😁

Here's a changelog:

• One big linting pass over the README.md file:
  • Markdown lint. Hence, the new .markdownlint.json file
  • LanguageTool lint
• New section to the README file regarding the “Settings” page
  • Add documentation regarding SSH keys and login password
  • Add heading for “Storage”, but I wouldn't really know what to write in there yet
• Change the SSH text in the HTML page,

Note that I did not test how the changes to the HTML page will render, as I didn't have an easy way to do so.

Cheers,

[Prodeguerriero]

This is related to issue #313

[Prodeguerriero]

By the way, given that I can't really contribute much besides documentation, if you want I could review the entire README file and update it.