dist: fix local-fs.target dependency

systemd man page says:

systemd-fstab-generator(3) automatically adds dependencies of type Before= to
all mount units that refer to local mount points for this target unit.

So "Before=local-fs.taget" is the correct dependency for local mount
points, but we currently specify "After=local-fs.target", it should be
fixed.

Also replaced "WantedBy=multi-user.target" with "WantedBy=local-fs.target",
since .mount are not related with multi-user but depends local
filesystems.

Fixes scylladb#8761

dist/common/scripts/scylla_coredump_setup

@@ -62,8 +62,7 @@ ExternalSizeMax=1024G
 [Unit]
 Description=Save coredump to scylla data directory
 Conflicts=umount.target
-Before=scylla-server.service
-After=local-fs.target
+Before=local-fs.target scylla-server.service
 DefaultDependencies=no
 
 [Mount]

dist/common/scripts/scylla_raid_setup

@@ -257,19 +257,18 @@ if __name__ == '__main__':
             dev_type = 'realpath'
         LOGGER.error(f'Failed to detect uuid, using {dev_type}: {mount_dev}')
 
-    after = 'local-fs.target'
+    after = ''
     wants = ''
     if raid and args.raid_level != '0':
-        after += f' {md_service}'
+        after += f'\nAfter={md_service}'
         wants = f'\nWants={md_service}'
     opt_discard = ''
     if args.online_discard:
         opt_discard = ',discard'
     unit_data = f'''
 [Unit]
 Description=Scylla data directory
-Before=scylla-server.service
-After={after}{wants}
+Before=local-fs.target scylla-server.service{after}{wants}
 DefaultDependencies=no
 
 [Mount]