logging: Remove logging v1 from the logging

Remove v1 implementation from log_core and all references in the tree.
Remove modules used by v1: log_list and log_msg.
Remove Kconfig v1 specific options.
Remove Kconfig flags used for distinction between v1 and v2.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>