Enhancement: Add Apprise support as a vendor

Hey guys,

This looks awesome, but it would be great if you included support for [Apprise](https://github.com/caronc/apprise) as a notification vendor
This would add out of the box support for many many more providers like Teams, twitter, telegram, etc.

Apprise has python libraries for easy integration
```python
import apprise

# Create an Apprise instance
apobj = apprise.Apprise()

# Add all of the notification services by their server url.
# A sample email notification:
apobj.add('mailto://myuserid:mypass@gmail.com')

# A sample pushbullet notification
apobj.add('pbul://o.gn5kj6nfhv736I7jC3cj3QLRiyhgl98b')

# A sample Microsoft Teams notification
apobj.add('msteams:///T1JJ3T3L2@DEFK543/A1BRTD4JD/TIiajkdnlazkcOXrIdevi7F/')

# Then notify these services any time you desire. The below would
# notify all of the services loaded into our Apprise object.
apobj.notify(
body='what a great notification service!',
title='my notification title',
)
```

The issue names no repository files, tests, or entry points. Start by locating existing notification-vendor integrations and the dispatch path, then compare their configuration and testing patterns with Apprise's Python library. Done means Apprise can be configured as a vendor and notifications are delivered through it.

Written by the indexing model from the issue text.