Make Release Worker work for unofficial builds #1050

Re nodejs/build#4499

Two ways I can think of for doing this,

1. Have a separate environment specifically for unofficial builds (my preferred way atm)
   • Same as prod config except R2_BUCKET env will point to a separate R2 bucket here
2. One prod deployment and we decide which bucket to read from based off of hostname

Regardless need to go through and make sure we're not doing any logic specific to dist-prod's structure that doesn't work for the unofficial builds setup, which we currently are with some of our routing logic