[tools] add write perm admin command

[coder-zzzz]

FEATURE REQUEST

1. Please describe the feature you are requesting.
   add addWritePerm admin command
2. Provide any additional detail on your proposed use case for this feature.
   sometime I can use wipeWritePerm to wipe some broker's wirte perms for a while, but reopen write perm need to restart broker , register it to nameserver again.
3. Indicate the importance of this issue to you (blocker, must-have, should-have, nice-to-have). Are you currently using any workarounds to address this issue?
   should-have, restart broker is the workaround way

[coder-zzzz]

I'll commit a pr to close it