Nic Patterson Interview

[reynn]

Updates included in this PR:

• Change from file based configuration to environment based configuration. Decided to use the minimal github.com/caarlos0/env library based on prior usage and 0 extra dependencies.
• Add Dockerfiles for existing service and client. Parameterized the Go version that will build the binary and used multi-stage build to keep final image size small.
• Added structured logging via the log/slog package available now in the Go standard library. Client uses the text handler and the Service uses the JSON handler.
• Add Github Actions for an initial continuous integration pipeline. This could be expanded later to include building and publishing the Docker images to a remote registry.
• Add Makefile with targets to build/test/run various components of the project.
• Add authservice-go to handle client authentication and jwt validation.