tree-wide: drop pwd.h and grp.h when user-util.h is included

src/basic/capability-util.c

@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <errno.h>
-#include <grp.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/prctl.h>

src/basic/user-util.c

@@ -2,8 +2,6 @@
 
 #include <errno.h>
 #include <fcntl.h>
-#include <grp.h>
-#include <pwd.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>