Link to relevant documentation in generated files

[rixx]

I think it could be very helpful to link to the relevant documentation sections in the generated files, so that it's easier for users to get going.

For example, the main __init__.py could include a docstring like

    """Plugin configuration.

    See https://docs.netbox.dev/en/stable/plugins/development/#pluginconfig-attributes
    for a list of all possible attributes."""

(Or shorter, or versioned, but you get the idea.)

When I start a new plugin and open a models.py or filters.py, I pretty much always want to look up the main tutorial or documentation anyway, and I imagine it's the same for most of us. Deleting the line if it's not that useful isn't much hassle either, as in the beginning, you move a lot of things around anyway.

(Happy to provide a PR if you think this is a good idea.)