chore(registry): Upgraded registry to 0.9
fix(*): Handling of unavailable services

Send 503 - Service Temporarily Unavailable for not running services

Fixes #2161
Merge pull request #2443 from johanneswuerbach/no-service

fix(*): Handling of unavailable services
Merge pull request #2439 from johanneswuerbach/registry-upgrade

chore(registry): Upgraded registry to 0.9
ref(builder): remove python and jq from the builder script. replaced by small go apps.
fix(builder): cleanup binaries after `make build`
ref(builder): use `docker create` for build target
fix(builder): avoid issues with non-string release values
fix(builder): supply empty default process type

Heroku buildpacks are not required to send one. If none is provided,
it should be an empty list.
test(tests): supply envvar with spaces
ref(builder): move sshd_config to etc/
ref(builder): move builder to image/, add unit tests

This move refactors some parts of the builder to go, as well as
allowing the possibility of re-writing the entire component in Go
in the future.