* Added 'mix' system support for Growatt integration
* Changed Growatt "Last Data Update" to a timestamp
* Changed Growatt "Last Data Update" to UTC
* Accepted suggested change for Growatt "Last Data Update"
Co-authored-by: Martin Hjelmare <marhje52@gmail.com>
Co-authored-by: Martin Hjelmare <marhje52@gmail.com>