Remove unused dependencies

[7-zete-7]

Idea

Remove obviously unused dependencies and discuss the need for not used by this template dependencies.

Dockerfile lines that will be discussed further:

symfony-docker/Dockerfile

Lines 20 to 25 in 178158c

	RUN apt-get update && apt-get install -y --no-install-recommends \
	acl \
	file \
	gettext \
	git \
	&& rm -rf /var/lib/apt/lists/*

Obviously unused dependencies

The following dependencies are not used in this template and their use is not implied in the projects:

• file
• gettext

Both of these dependencies were originally added in #51.

Dependencies not used by this template

The following dependencies are not used in this template, but may be required for some features:

• acl — To use the setfacl command. This command is not needed by this template (FrankenPHP runs as root, there is no need to grant permissions for www-data). However, this command may be required for those running FrankenPHP as an unprivileged user (see Run container as an unprivileged user  #679).
• git — To work with Git in the container. It is also an optional dependency for Composer.