The behavior pack download doesn't include a blocks.json file.

When downloading the Vanilla Behavior Pack file from https://www.minecraft.net/en-us/addons, the file does not include a blocks.json file. This is terribly inconvenient for trying to create new blocks to add into the game.

1. Steps to Reproduce:
   1. go to https://www.minecraft.net/en-us/addons
   2. download Vanilla Behavior Pack
   3. unzip the folder
   4. open the unzipped folder
   5. see that there's no blocks.json file

Observed Results:
There is no blocks.json file

Expected Results:
There would be a blocks.json file