This can be used to inform callers that the operation is cancelled.

Check for operation status when streaming operations.
Allows client to catch a cancelled job.

Removed state machine. Will help with #66.

This will describe and configure hardware.

Also move `bot_session` to simply `session`.

This will contain the information about a running task
and lease.

This will manage the Tenant objects.

Also Moved bot_interface.py to interface.py.

Also moved the initialisation of these variables to
the `__init__` of `session.py`.

Also adds cancellation tests.

Mostly due to removing the state machine in the BotsService

Hash type, batch size and symlink strategy.