fix: more reliable linking

[sentialx]

Fixes issues with linking DHD or Transport Rings when a block position changes.

[MrJake222]

Your pull requests/commits/code could use some comments. So what's the deal with the linkId?

Edit: Is it used anywhere? I don't seem to find it's uses beside getters/setters/saving to NBT

[sentialx]

Normally when you move the gate with DHD to a place where there is a DHD already, it tries to connect to the DHD regardless of its previous connection. linkId property is meant to solve that problem.

[MrJake222]

I'd never guessed that. Please add some comments (see how to create JavaDoc, basically start the multiline comment with /**) to the fields and methods using it.