Implement level comment likes.

[RealistikDash]

Currently, trying to like a level comment raises a NotImplementedError.

https://github.com/RealistikDash/RealistikGDPS/blob/d259ee3430a581df2e54f8ab468f3c26b602ec25/rgdps/api/gd/user_comments.py#L122-L132

This function can reuse existing backend infrastructure.

A rewrite of how this function is used could be useful. Instead of an if statement at the handler level, a single like_target function could be used with an enum.