docs: Significant tidy-up and simplification, add porkbun protocol

[domdomegg]

These changes:

• Reduce duplication between pages
• Provide examples to get started more easily
• Explain what routers and protocols actually are
• Sorts protocols alphabetically, to make it easier to find the relevant protocol
• Removes out of date information
• Make minor formatting tweaks

[domdomegg]

Requesting review from @LenardHess

[LenardHess]

Looks great!

Please fix the merge conflicts and then I'll merge it

[domdomegg]

Great, thanks! I've resolved the merge conflicts including adding in the section from #2

[domdomegg]

Hi @LenardHess, I've fixed the merge conflicts :)

[LenardHess]

Thanks, merged 👍