* Move central/peripheral setting to Kconfig.defconfig files to allow left/right .conf files to override central/peripheral role for splits.
Aligns *.h and *.c to underscore naming convention. These were kept (with warnings) for backwards compatibility with external boards/shields: - kscan-mock.h - matrix-transform.h They should be removed in the future. PR: #523
Ran all the default keymaps through the keymap upgrader and manually adjusted alignment.
