New plugins: HomeAssistant and Shelly for PSUControl

Hi guys, I was inspired by the plugin system for PSUControl and since I'm an avid user of HomeAssistant and had a Shelly 1 relay laying around, I decided to create two plugins at once:
Configuration instructions can be found in the repos.

They have not been published to the repository yet, so if you'd like to use them please install them from these links:

Any feedback, bugs or feature requests are more than welcome.