Provide more helpful message for kedro airflow create -h

[noklam]

Description

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The current CLI help message isn't very clear, we can probably reuse some of the message from kedro or just copy it over.

Context

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Possible Implementation

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Possible Alternatives

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[ankatiyar]

I believe this has more or less been completed by @sbrugman. #233

Usage: kedro airflow create [OPTIONS]

  Create an Airflow DAG for a project

Options:
  -p, --pipeline TEXT         Name of the registered pipeline to convert. If
                              not set, the '__default__' pipeline is used.
  -e, --env TEXT              Kedro configuration environment name. Defaults
                              to `local`.
  -t, --target-dir DIRECTORY  The directory path to store the generated
                              Airflow dags
  -j, --jinja-file FILE       The template file for the generated Airflow dags
  --params TEXT               Specify extra parameters that you want to pass
                              to the context initialiser. Items must be
                              separated by comma, keys - by colon or equals
                              sign, example: param1=value1,param2=value2. Each
                              parameter is split by the first comma, so
                              parameter values are allowed to contain colons,
                              parameter keys are not. To pass a nested
                              dictionary as parameter, separate keys by '.',
                              example: param_group.param1:value1.
  -h, --help                  Show this message and exit.

[astrojuanlu]

Further improvements always welcome of course :) Closing for now!