Adding caching system to reduce request

As mentionned, Viessmann as set 2 limit to their API:
120 calls for a time window of 10 minutes
1450 calls for a time window of 24 hours

I have done a refactoring to add cache. Once you are creating the ViessmanApi object it will do only 4 request and subsequent call on method will use cache.
So it's highly recommanded that you merge all your php file in a single one!!!!
For instance doing in one php file those method call will result in a total of 4 request.

<?php
include DIR . '/bootstrap.php';
echo "Température extérieure " . $viessmannApi->getOutsideTemperature() . “\n”;
echo "Température boiler " . $viessmannApi->getBoilerTemperature() . “\n”;
echo "Pente " . $viessmannApi->getSlope() . “\n”;
echo "Parallèle " . $viessmannApi->getShift() . “\n”;
echo "Mode chaudière " . $viessmannApi->getActiveMode() . “\n”;
echo "Programme actif " . $viessmannApi->getActiveProgram() . “\n”;
echo "Is Heating Burner active ? " . $viessmannApi->isHeatingBurnerActive() . “\n”;//in php false bool is converted into empty string
echo "Is Dhw mode active ? " . $viessmannApi->isDhwModeActive() . “\n”;
echo "Température de confort " . $viessmannApi->getComfortProgramTemperature() . “\n”;
echo "Température écho " . $viessmannApi->getEcoProgramTemperature() . “\n”;
echo "Température externe " . $viessmannApi->getExternalProgramTemperature() . “\n”;
echo "Température réduit " . $viessmannApi->getReducedProgramTemperature() . “\n”;
echo "Est en veille ? " . $viessmannApi->isInStandbyMode() . “\n”;
echo "Température eau chaude " . $viessmannApi->getHotWaterStorageTemperature() . “\n”;