i3c: add i3c shell

Add an I3C shell. This includes support of all I3C CCC commands that
currently have helper functions implemented. This also includes all
the read/write shell commands that the i2c shell supported. An Info
command is also provided which will print out all i3c and i2c info
of an i3c bus. Only SDR read/writes are currently implemented.

Signed-off-by: Ryan McClelland <ryanmcclelland@meta.com>