Pypowerwall

* Added additional error handling logic to clean up exceptions.
* Proxy: Added command APIs for setting backup reserve and operating mode.

* Added 5 minute cooldown for HTTP 503 Service Unavailable errors from API calls.
* Proxy: Added DISABLED API handling logic.

options:
-h, --help show this help message and exit

commands (run <command> -h to see usage information):
{setup,scan,set,get,version}
setup Setup Tesla Login for Cloud Mode access
scan Scan local network for Powerwall gateway
set Set Powerwall Mode and Reserve Level
get Get Powerwall Settings and Power Levels
version Print version information

* Refactored pyPowerwall by emptywee in https://github.com/jasonacox/pypowerwall/pull/77 including:
* Moved Local and Cloud based operation code into respective modules, providing better abstraction and making it easier to maintain and extend going forward.
* Made meaning of the `jsonformat` parameter consistent across all method calls (breaking API change).
* Removed Python 2.7 support.
* Cleaned up code and adopted a more pythoinc style.
* Fixed battery_blocks() for non-vitals systems.

* Added logic to pull string data from `/api/solar_powerwall` API if vitals data is not available by jasonacox in 76.
* Added alerts from `/api/solar_powerwall` when vitals not present by DerickJohnson in 75. The vitals API is not present in firmware versions > 23.44, this provides a workaround to get alerts.
* Allow customization of the cachefile location and name by emptywee in 74 via `cachefile` parameter.

python
Example
import pypowerwall
pw = pypowerwall.Powerwall(
host="10.1.2.30",
password="secret",
email="meexample.com",
timezone="America/Los_Angeles",
pwcacheexpire=5,
timeout=5,
poolmaxsize=10,
cloudmode=False,
siteid=None,
authpath="",
authmode="cookie",
cachefile=".powerwall",
)

* Updated logic to disable vitals API calls for Firmware 23.44.0+
* Added rate limit detection and cooldown mode to allow Powerwall gateway time to recover.