Rework the devserver help to make it much easier to use.

After debugging and working with others to debug their issues with the
devserver, it has become clear that the devserver help is awful. This CL
does a much needed touch up on the devserver help message. Now you get
a full doc with options grouped based on who should use them. For the most part
most people should only ever need data_dir, port, and -t. Please take a look
over both the main docstring and which group I put each option in and let
me know if you disagree.

I also started the work in deprecating for_vm and replacing it with
no_patch_kernel.

BUG=chromium:225129
TEST=--help and also ran with every combination of --for_vm and
--no_patch_kernel.

Change-Id: Ic8d2c8519e7c9d4737a8e24ae44cbfe5f9ee1c84
Reviewed-on: https://gerrit.chromium.org/gerrit/46937
Tested-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Chris Masone <cmasone@chromium.org>
Commit-Queue: Chris Sosa <sosa@chromium.org>
2 files changed