Isoline and refactor

Add

• Routing V8: add new transport mode "bicycle" and "scooter";
• Routing V8: add alternatives parameter;
• Routing V8: add units (metrics/imperial);
• Routing V8: add via parameter (thanks to @cgarde89);
• Isoline: add Isoline integration;
• Adding test suite;
• LatLong added magic method toString() (thanks to @cgarde89);

Change

• Fix Phpstan warnings (level 6) (thanks to @creativenull)
• Refactoring base classes avoiding Singleton design pattern, and introducing DI;
• update examples/* and Readme file