[gardena] merge automower plugin

[RandomReaper]

Since the automower plugin share some code with gardena, I think both plugins should be merged.
Husqvarna mowers could be a new Things type (husqvarna_mower?).

Benefits:
bugs like #12980 and #12980 can be handled only once.

[lolodomo]

Since the automower plugin share some code with gardena

Do you mean they share the same API?

[RandomReaper]

Since the automower plugin share some code with gardena

Do you mean they share the same API?

They share at least the same account and the login API.

[andrewfg]

They share the same authetication API, but they use quite different API's for the actual functionality.

https://developer.husqvarnagroup.cloud/apis

So I am not convinced that merging these two bindings would make any sense at all.

[andrewfg]

I think that with #13263 the authentication issue of the OP #12980 has been resolved. So I am closing this one now.