Add --enable=all to ShellCheck by default

Change enforced shell type from dash to sh and excluded
SC2039 and SC3043 by default. local keyword is accepted by all
POSIX shells from practical point of view. There is no need anymore
to enforce dash so local is accepted.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: szubersk <szuberskidamian@gmail.com>
Closes #13020