This is now also the new default, since we can't provide a sane default URL
anyway.

WARNING: this can cause duplicate worker information in the Manager's
database.

This makes it easier to re-register workers; now this can be used, rather
than editing ~/.flamenco-worker.cfg. Since that file is likely to have been
created by the Worker itself, the user may not even know it exists.

This can be passed to the Worker using the {blender} variable definition
instead.

This makes debugging configuration issues easier. When the file does not
exist, the absolute path of its expected location is logged.

Also moved from os.path to using pathlib.

The new task types are actually used by Flamenco Server.

This passes the current hostname and list of supported task types to the
manager.

This allows a finer granularity of task selection for a given worker.

This is now implemented for Blender renders, merging of EXRs, and files
copied using the 'copy_file' command.

These zips contain the Wheel, an example configuration, README and LICENSE
files, and system integration files.