Improve Heatmap Service

[erlewa]

This PR brings two improvements:

1. Heatmap granule data is now transferred as binary using bincode dramatically reducing file sizes and thus reducing latency for the heatmap client
2. The existing Dockerfile has been brought up to date and will now run the service inside a docker container.
3. All dependencies existing in multiple workspace have been moved into root workspace Cargo.toml

[segallagher]

Looks good

[kalebvonburris]

Minor rust version issues.