the future ACME parameters. Tests written and passing.
WIP: added envy dependncy and ConfigOpts structs that will constitute Diplonat's configuration
WIP: ConfigOpts from_env() and validate() methods written. No API change (the env names remain unchanged)! Now need to use our new ConfigOpts struct instead of Environment, and update references to the environment variables in the code.
WIP: RuntimeConfig with business logic done. Tests written, but they are all running from the same process - setting environment variables in each test produces incoherent results. Another solution for testing is needed.
WIP: tests are fully written using 'from_iter' and all passing
