doc: start draft of go1.18 release notes, move go1.17 to x/website
This template is based on CL 295209 and previous ones like it.
Continue to eagerly include often-used sections, and clarify that
the TODO is about completing the section, or removing if it turns
out not to be needed.
Move the Go 1.17 release notes to x/website, since that's the new
home for past Go release notes as of CL 291711. They're added to
x/website in CL 342089.
For #47694
Updates #44513
Change-Id: I24962eed800d1509bdf71b7d7f819a683eb96f8f
Reviewed-on: https://go-review.googlesource.com/c/go/+/342070
Trust: Carlos Amedee <carlos@golang.org>
Run-TryBot: Carlos Amedee <carlos@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>