[L] Change in coreboot[main]: Documentation: Add information about the site-local directory

[Martin L Roth (Code Review)]

Attention is currently required from: Nicholas Chin.

Martin L Roth has posted comments on this change by Martin L Roth. ( https://review.coreboot.org/c/coreboot/+/87185?usp=email )

Change subject: Documentation: Add information about the site-local directory
......................................................................

Patch Set 1:

(1 comment)

File Documentation/getting_started/site-local.md:

PS1:
> There is already `tutorial/managing_local_additions. […]

Okay,but this isn't a tutorial,and it covers the entirety of using site local, so it's different.

I see a few options:
- Leave both as they are.
- Don't document the rest of site-local since a piece is covered in the tutorial.
- Remove the duplicate coverage from one place or the other.
- Remove the tutorial.

To me, the only one of these that really makes sense is to cover them in both places. A tutorial is a completely different sort of document, so it seems reasonable to have information duplicated there.

Thoughts?