Flamenco Manager now has a "storage path" config option, which will be
used by Shaman if enabled. Now the `{jobs}` implicit variable will always
exist, its value depending on whether Shaman is enabled or not.
Flamenco v2 allowed separate configuration of the Shaman file store and
checkout paths. This is now just one setting for "the storage". The file
store will be in `{storage}/file-store` and the checkout will happen in
`{storage}/jobs`.
This is not yet working, it's just a direct copy of the Manager of Flamenco
2, with Logrus replaced by Zerolog. The API has been documented in
flamenco-manager.yaml as a starting point for the integration.
