Add allowed client version range as a configuration option

When running a network that only accepts the latest versions (or at the very least, not the full range of 1.8-1.18), it would be great if there was a configuration option that defined the client versions that are allowed to connect. If you connect with a version not allowed, it would disconnect you with a message showing "This server is only compatible with Minecraft versions 1.17.1-1.18" (or whatever version range you defined). This is already partially possible with a plugin, but it becomes a bit messy if you use modern forwarding because Velocity drops connections from clients older than 1.13 before plugins get a chance to change the message.

Start by reading proxy/src/main/java/com/velocitypowered/proxy/connection/client/HandshakeSessionHandler.java, especially the handshake path linked in the issue, and trace how client versions are currently accepted or rejected. Determine where configuration is loaded and where the disconnect message is chosen. Done means configured client version ranges are enforced and rejected clients receive the configured range in the message.