Trying out cargo chef and a travis docker image cache. (#1238)

Trying out cargo chef and a travis docker image cache. (#1238)

* Trying out cargo chef and a travis docker image cache.

* trying to change internal target.

* Use latest cargo-chef with --target

* Remove caching for now.

* Adding back in chowns

* Adding back in cache.

* Remove travis caching.

* Switching dev dockerfile to match prod, using cargo-chef and alpine.

* Make travis happy

* Trying a chown rust.

* Caching cargo-chef first.

* Moving the chowns

* Removing many copy commands.

* Go back to rust 1.47.0 due to config-rs breaking.

* Adding the old volume mount version.

* Adding some script comments.

Co-authored-by: Luca Palmieri <lpalmieri@truelayer.com>