feature branch: use Symfony docker

[COil]

Use dunglas/symfony-docker to run the project with Docker instead of the Symfony binary.

Q	A
Branch?	symfony-docker
Cleanup?	no
Bug fix?	no
Fixed tickets	NA
New feature?	yes
Doc added?	no
Tests pass?	yes
Deprecations?	no
License	MIT

[COil]

I'm considering using this template for a side project and I would love to use Docker with it, so here's my review :)

Would you like to do the rebase ?

[florentdestremau]

Oh I can try yes, will try to find some time in the days to come