Add url twig extension (sulu#15)

* added url twig extension

* added documentation

* fix php-cs

* added tests and changed functionality

* added documentation

added intl_countries, intl_languages, intl_locales twig extensions (s…

…ulu#14)

allow to give source format as string (sulu#5)

add test setup and phpcs check to circle ci (sulu#3)

add service and componentlist output (sulu#1)

add documentation for web component twig extension