Support for Nautobot 1.1.0 (Celery)

[mzbroch]

PR implements Celery support and provides Nautobot 1.1.0 compatibility:

• Celery's availability is determined by try/except attempt during import of nautobot.core.celery.
• New middleware onboard_device_worker function per worker type (Celery, RQ)
• Credentials object received nautobot_serialize and deserialize methods as per Nautobot-core

[glennmatthews]

Is this code actually needed? Custom serialize/deserialize methods should only really be needed as special-case handling where things aren't trivially encodable to JSON. If we need this for even as simple a data model as this, I'm a bit concerned.

[mzbroch]

There are two related aspects of the Credentials() class:

• This simple data model does not require a class itself to store the data, agreed.
• This simple class was created to prevent credentials from being printed to stdout (by overriding __repr__(), which works just perfectly)

To keep # 1 and # 2 I believe we have to support these methods - when I did not do this, class' serialization has not been working correctly.

[glennmatthews]

Thoughts on the try/except pattern versus checking settings.VERSION for <1.1 versus >= 1.1 and making a decision based on that?

[mzbroch]

We did version based decision in https://github.com/networktocode/ntc-netbox-plugin-onboarding/blob/develop/netbox_onboarding/release.py:

• it requires to parse the version with package.version,
• code has several places with version-centric, conditional logic based on if statements,

Both approaches are similar in an end effect, with the first choice being a simpler/more readable in context of this particular change.