Migrate from asyncio-mqtt to aiomqtt

[mweinelt]

Describe the bug The asyncio-mqtt project has been renamed to aiomqtt. The old project name receives no updates anymore.

To Reproduce

• Observe how https://github.com/sbtinstruments/asyncio-mqtt redirects
• Check https://pypi.org/project/asyncio-mqtt/#history
• Check https://pypi.org/project/aiomqtt/#history

Additional context https://sbtinstruments.github.io/aiomqtt/migration-guide-v2.html

[MartinHjelmare]

A PR is welcome. Thanks!