docs: remove the tips on how to submit patches from MAINTAINERS

Having "how to submit patches" in MAINTAINTERS seems out of place.
We have a whole section of documentation about it, duplication
is harmful and a lot of the text looks really out of date.

Sections 1, 2 and 4 look really, really old and not applicable
to the modern process.

Section 3 is obvious but also we have build bots now.

Section 5 is a bit outdated (diff -u?!). But I like the part
about factoring out shared code, so add that to process docs.

Section 6 is unnecessary?

Section 7 is covered by more appropriate docs.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20230630171550.128296-1-kuba@kernel.org>

docs: rename development-process/ to process/

As we'll type this a lot, after adding CodingStyle & friends,
let's rename the directory name to a shorter one.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>