Update docs for first timers.

[louisdvs]

As a total new comer to go, I stumbled on the docs a little.

I updated them to reflect how I got it working so not sure if this is helpful or not (feel free to can it).

Awesome work pulling this repo together. Thanks!

[skydado]

+1

I took me a while to understand that:

1. I need to restart HA to see the newly added Addon
2. There is a configuration tab in the Addon, where to put user+pwd etc. Needed to update the image through a SSH connection, instructions here
3. I need to install Mosquitto addon and create a specific mqtt user for it, the same you need to config in the CoSungrow configuration page