add buildenv to interactively build program

- added s3cmd to upload archives
- to upload archives, you need to have the following env variables setup in
  the host
  - AWS_ACCESS_KEY
  - AWS_SECRET_KEY
  - AUTOPARTS_HOST
  - AUTOPARTS_BUCKET

To use the buildenv, build base image first with `make base`, and then enter the build env with `./script/buildenv`