Allow place command to take random sequences as an optional parameter

Currently the use of "/place jigsaw ..." is limited by the command using the combination of world seed and x/z coordinates to generate a structure.

This limits the usefulness of "/place jigsaw ..." as the location would have to be changed in order to generate a different structure.

A usecase that would require being able to pass in a random sequence is a minigame/map like infinity dungeon. Currently this has to use various rather hacky solutions to select and populate the playspace.

Being able to pass a random sequence to /place would allow it to handle the heavy lifting instead and leverage features of the jigsaw system.