chore: add docs for sharing ports

[f0ssel]

After taking a look at our existing documentation, it made the most sense (to me personally) to add what we have drafted to the existing Port Forwarding docs. I know this page is very long, but I think this page should probably be looked at holistically in a separate effort to re-organize this docs page.

@stirby I left a few redundant images out and moved things around slightly, feel free to dive into this and make suggestions or changes as you see fit directly to the PR if you'd like.

Todos:

• update any old screenshots to match new ones

[stirby]

Great addition

[stirby]

I made some minor copy changes and promoted all the new headers to allow "Configure maximum port sharing level" to render the enterprise label.

Before:

After: