Input preferences: Use BControlLook::ComposeIconSize().

And do some other cleanup while at it.

Fixes #17919.

Input preferences: some style fixes.

Problems found by running haiku-format and looking at the resulting
files. Manually triaged to keep only the correct changes, currently
haiku-format is making a lot of unwanted changes as well.

Merging the correct changes allows us to see the incorrect ones more
easily and continue working on fixing them.

Input preferences: fix list minimum size

- Use the longest device name as a min size
- Refactor things a bit to simplify the code
- Also set weights in the top group view to ensure a nice ratio between
the list and the other part of the window

Input: add icons to the DeviceList

Change-Id: I2eaebca0f0e91e3420b7e63a4a568f4e658af253
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2722
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

Connected Devices: Mouse, Touchpad and Keyboard

-Resolve some issues.
-Added the connected devices code in the main window.
-Replace BUTTON_DEFAULTS and BUTTON_REVERT with kMsgDefaults and kMsgRevert.

Change-Id: I3b0c86fc581056859239df0fbf2c085b8d168136
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1619
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

Input preferences: fix build

One file was accidentally missing from this commit and was added to the
next one (which isn't ready for merging yet). Add it back here instead.