PHP POST and UPLOAD max size setup

[leopoletto]

This PR allows users to set up PHP post_max_size and upload_max_filesize using the docker-composer.json file.

The php.ini files in each runtime folder wouldn't be necessary anymore. Instead, the DockerFile has two new arguments (PHP_POST_MAX_SIZE and PHP_UPLOAD_MAX_FILESIZE) that allow setting up the desired values. By default, the php.ini content stays the same, of course.

To override the default value:

[taylorotwell]

Hey there - you can fork or publish and add this to your own setup if you want. 👍

[leopoletto]

Thank you!