Use JWT to handle API tokens

[pH-7]

To manage the user tokens, use JWT library instead https://github.com/firebase/php-jwt that help encoding and decoding JSON Web tokens.

Food-Scanner-API-Backend/FoodScanAppService.php

Lines 121 to 123 in 28e5633

	case Security::UPDATE_USER_TOKEN:
	case Security::TEST_ENCRYPTION:
	case Security::REFRESH_TOKEN: