Fusion-solar-py

* Added tests for README examples
* Added query time to get_battery_day_stats (by jgonzalezzitu)
* Updated client error handling due to new FusionSolar error messages
* Fixed str to float converion in battery stats (by MatteoGheza)
* Fixed typos in README
* Added functions get_historical_data and get_real_time_data (by Nikolai Raitsev)
* Fixed issu in encryption.py (by MatteoGheza and ATNALDC)

* Added support for the new `roarand` header which is required for several function calls.

* Added support for the new encrypted login function introduced in API version 3

* Added new function `get_current_plant_data`

* Added new functions `is_session_active` and `keep_alive`
* Adapted the logged_in wrapper to use this new function

* Fixed detection of incorrect subdomains
* Added test for session reuse
* Removed deprecation decorators from PowerStatus as these clashed with property
decorators (functions will still be removed in the future)