Improve boot time

[imlucas]

Template tag or something so we don't have to wait to unpack the payload zip before we can test if its already in temp.

As well, including offsets will make startup time of apps dramatically faster to startup as we can statically fseek on the contents:

{
   "offsets": {
     "node": [0, 18371812],
     "app": [18371813, 24786323]
   }
}