s3:winbind: Refactor check_info3_in_group() to take a wbint_SidArray struct

s3:winbind: Refactor check_info3_in_group() to take a wbint_SidArray struct

Refactor the check_info3_in_group() function to take a wbint_SidArray
struct. The sid strings stored in extra_data are parsed into a
wbint_SidArray in a separated function.

Later, winbindd_dual_pam_auth() will be converted to a local RPC
call handler and the wbint_SidArray containing the required membership
will be part of the 'r' struct.

Signed-off-by: Samuel Cabrero <scabrero@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>