[Enhancement] Allow installation via PHP Composer

[schams-net]

Problem

While not overly complicted, the installation process requires some manual steps. Also, some dependent libraries are currently stored "hard-coded" in the project folder.

Suggested Solution

Composer is a widely used PHP dependency management solution that simplifies the installation and ongoing updates of PHP projects and their dependencies.

Changes Required

• Develop a central control file composer.json.
• Restructure folders (e.g. Composer creates a vendor/ directory).
• Update references to libraries (new paths.).

[BenjaminHae]

Can be done within the course of #235.

[zeruniverse]

Goto #248