Randomized block selection for placement by drone

[johalun]

Describe the feature

A checkbox in the place widget "Randomize" which when enabled will make the drone to pick a random stack from the valid stacks in its inventory.

Reasons why it should be considered

This is an important feature for any build. Rarely do we want only a single block type in a build, but rather use a palette of different blocks. For example, in order to build a floor made of 80% stone and 20% andesite you would ensure that the drone/pc always has 4 stacks of stone and 1 stack on andesite in its inventory. With randomize enabled, the drone would pick one random stack of these 5 to take a block from and place in the world, for each block placed.

Additional details

I might take a stab at this and make a PR if I can find the time but that might not be possible for some time. I think the implementation should be very simple and straightforward. If implemented, I'd love to see it also backported to 1.20.1.