Code is now compatible with PHP8

[Bal2018]

Feature/ Issue Description

Code was giving issues with using php 8 on my local when the packages initially installed were for php 7.4.
The final issue I came across was Script security-checker security:check returned with error code 1.
Discovered that "symfony/(recently) got rid of its security package and so had to uninstall this.

Code Explanation

Updated :

 composer update infection/infection --with-dependencies
 composer update doctrine/orm

And uninstalled :
composer remove sensiolabs/security-checker

In the code base updated .env file to include app path and correct port number

[pavlakis]

@Bal2018 can you update this to be "^7.4 || ^8.0"