AIP-72: Moving BaseOperatorLink to task sdk

[amoghrajesh]

Why?

We moved the BaseOperatorLink to use a new machinery in #46609. BaseOperatorLink should reside now in the task sdk instead of models. This PR attempts to do that.

Testing

I have defined some plugins:

from airflow.plugins_manager import AirflowPlugin
from airflow.sdk.definitions.baseoperatorlink import BaseOperatorLink
from airflow.providers.standard.operators.python import PythonOperator


# define the extra link
class HTTPDocsLink(BaseOperatorLink):
    # name the link button in the UI
    name = "HTTP docs"

    # add the button to one or more operators
    operators = [PythonOperator]

    # provide the link
    def get_link(self, operator, *, ti_key=None):
        return "https://developer.mozilla.org/en-US/docs/Web/HTTP"

# define the plugin class
class AirflowExtraLinkPlugin(AirflowPlugin):
    name = "extra_link_plugin"
    operator_extra_links = [
        HTTPDocsLink(),
    ]

DAG used:

from airflow.models.dag import DAG
from pendulum import datetime

from airflow.providers.standard.operators.python import PythonOperator


def handler():
    print("Hello from the python operator!!")

with DAG(
    dag_id="extra_links_plugin",
    start_date=datetime(2022, 11, 1),
    schedule=None,
    catchup=False,
    tags=["extra_links"],
):

    call_api_simple = PythonOperator(
        task_id="call_api_simple",
        python_callable=handler,
    )

Loaded in UI:

Green run:

Button:

---

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[amoghrajesh]

Finally got a green run on this one!

[ashb]

Overall LGTM, a few nits/small changes. Pre-approving once those are done

[amoghrajesh]

Damn this will need a rebase now!

[amoghrajesh]

Just rebased it, will wait for the CI and merge :)