docs: Fix broken links in documentation

[librellito]

Issue

Found several broken links while browsing the documentation:

• Link to installation guide in README returns 404
• Configuration reference link is outdated

Happy to submit a PR fixing these.

Found during documentation review

[tangyuan0821]

I'd like to work on this

[StanFromIreland]

Please wait, the OP said they would like to. OP go ahead!