parse-maintainers: Do not sort section content by default

Add an --order switch to control section reordering.
Default for --order is off.

Change the default ordering to a slightly more sensible:

M:  Person acting as a maintainer
R:  Person acting as a patch reviewer
L:  Mailing list where patches should be sent
S:  Maintenance status
W:  URI for general information
Q:  URI for patchwork tracking
B:  URI for bug tracking/submission
C:  URI for chat
P:  URI or file for subsystem specific coding styles
T:  SCM tree type and location
F:  File and directory pattern
X:  File and directory exclusion pattern
N:  File glob
K:  Keyword - patch content regex

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>