If Shaman is used to submit the job files, store the job's checkout ID
(i.e. the path relative to the checkout root) in the database. This will
make it possible in the future to remove the Shaman checkout along with
the job itself.
Instead of erroring out when a symlink already exists, investigate it. If
the linked file is the one that's intended, just use it.
For some reason, BAT and/or the Flamenco add-on include some files twice
in the checkout request to Shaman. This is now handled gracefully.
`os.IsNotExist()` is from before `errors.Is()` existed. The latter is the
recommended approach, as it also recognised wrapped errors.
No functional changes, except for recognising more cases of "does not
exist" errors as such.
Shaman was made on Linux, using the `path` module, which only supports
forward slashes. This mostly replaces `path` with `path/filepath` to use
native paths and increase Windows compatibility.
The work isn't done yet, though.
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`.
Only add a random suffix to the checkout dir if it is necessary to ensure
uniqueness. If the client-supplied checkout directory doesn't exist yet,
it will be used as-is.
This introduces some more conceptual changes to Shaman. The most important
one is that there is no longer a "checkout ID", but a "checkout path".
The Shaman client can request any subpath of the checkout directory,
so that it can handle things like project- or scene-specific prefixes.
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.
