mgmt: Added Kconfig values and west.yml changes for mcumgr new version

The new version of mcumgr adds a few new Kconfig values, so
this commit adds them on Zephyr side.
This commit also updates west.yml so it points to the latest
changes on mcumgr's repo.

Signed-off-by: Miguel Azevedo <miguellazev@gmail.com>
Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>