add clickable dest signs

[Huskydog9988]

Dest signs are denoted with [DEST] or [DESTINATION] on the first line. A dest sign can have one dest per remain line on the sign. Players can punch the sign to cycle through the available dests. Destinations prefixed with "/dest " will have the prefixed removed automatically.

fixes: #690

[Protonull]

imo, it should be [DESTINATIONS] to distinguish it from [dest]/[!dest] junction signs

[okx-code]

I agree this needs to be clearly distinguished from regular destination signs, like the first line should be [set destination] or something

[Huskydog9988]

I wanted players to be able to use existing dest signs as they already exist, plus I don't feel the ambiguity is all that detrimental. I also think that just having a single "railswitch" sign is easier to understand then having multiple different kinds that end up just looking the same.

[Protonull]

For what it's worth, I went with [set destination] for ClickDest which definitely no one uses since it's illegal. I could've gone with [dest] as you've done, it would give a layer of plausible deniability, but I do think gives a confusing dual purpose to those signs. I cannot read your mind, but I assume it's the same reason as why [!dest] signs aren't also supported in this PR despite having the exact same purpose (just a different redstone output).