Added Element Integration

[marcopedrinazzi]

Hi! I have added an Element Integration with Maubot and its Maubot-Webhook plugin ( maubot and maubot-webhook ) the template that I used for maubot webhook is

path: /send
method: POST
room: '...'
message: |
    {{ json.msg }}
message_format: markdown
auth_type: Basic
auth_token: username:password
force_json: false
ignore_empty_messages: false

A demo screenshot of the result:

The look is very similar to the one used for Teams

I have not updated the README.md due to the presence of the great flow-image you created and because I wanted to let you test the Element integration first.

By the way, congrats and thanks for the great tool 💯