including the relays not found in the consensus.
Also:
- rename `generate` fn to `append_outcfg`
- split the function so that it can be call from tests with an empty
  `Relay`s vector
- add `root_path` as argument to the function to pass different root
  directories for tests
- replace some `&str` arguments by `Path` as reference, so that the
  functions can accept path in several formats

Closes #33