Allow Symfony 5 and fix compatibility

[damienalexandre]

Allow Symfony 5 and fix the following:

• As the tests where only running on PHP 7.0, only Symfony 3.4 was tested
• The TreeBuilder was not compatible with SF 4.2
• Parameters should be case sensitive

[damienalexandre]

I did not test on a real SF5 application yet and the tests are not covering everything. I will report soon.

[damienalexandre]

• removed Symfony 2 support
• added tests for the Controllers
• removed @Template annotation usage but kept @Route, it could be switched to the framework native annotation
• ignored all deprecations

I don't have time to go further.

[lenybernard]

Thank you @damienalexandre 🎉