Improve the ease of running the example services

[robbkidd]

With more folks interested in running these example services, we can make running them easier. We've got a combination of Tilt and Docker Compose to run some things as processes directly on the host and other things as Docker containers.

Improvements to consider:

• Run everything in containers to reduce the complexity of needing compilers and runtimes installed on the host
  • Bonus for this one: the Redis contain would not need its port forwarded to the host's loopback address, something today that conflicts with any other concurrent use of Redis on the host for some other purpose.
• A parent Tiltfile to run everything or some selection of everything
• A Tiltfile in each language directory to run all the services for one language

[vreynolds]

Also: additional documentation to ease discoverability of what to run for different use cases. (e.g. just need a little bit of data from one service? --> run year-service)