email pipeline_failure_sensor

Summary:
Similar to D8510, this diff provides out-of-box support for sending emails on pipeline failures over the SMTP

This is thin layer that doesn't address advanced (more secure) email auth connection.
So if an OSS user wants a more secure mechanism we could direct them to write their own.

from dagster import repository
from dagster.utils.email import make_email_on_pipeline_failure_sensor

email_on_pipeline_failure = make_email_on_pipeline_failure_sensor(
    email_from=os.getenv("ALERT_EMAIL_ADDRESS"),
    email_password=os.getenv("ALERT_EMAIL_PASSWORD"),
    email_to=["yuhan@elementl.com"],
    dagit_base_url="http://localhost",
)

@repository
def my_repo():
    return [my_pipeline, email_on_pipeline_failure]

api doc:

One thing is open for discussion is how we get the email creds like sender email password.
This diff asks users to put sender email and password directly.
Alternatives are:

1. ask for env vars instead
2. to have an entry in the Dagster instance yaml to get those types of configs/tokens.

Test Plan:
toy sensor and got emails

Reviewers: sandyryza, prha, owen

Reviewed By: sandyryza

Differential Revision: https://dagster.phacility.com/D8516