Introduced 'GNRC_PKTDUMP_MSG_QUEUE_SIZE_EXP' to hold exponent
value and made GNRC_PKTDUMP_MSG_QUEUE_SIZE dependant on
GNRC_PKTDUMP_MSG_QUEUE_SIZE_EXP.
Moved 'GNRC_PKTDUMP_MSG_QUEUE_SIZE_EXP' to 'CONFIG_' namespace.
Exposed configurations to Kconfig
Co-authored-by: Martine Lenders <mail@martine-lenders.eu>
Co-authored-by: Leandro Lanzieri <leandro.lanzieri@haw-hamburg.de>