Include support for multiple extension installs with different version on the same site

[robert81]

Right now it is not possible to run multiple WSAL instances which have a different version of the template core. For them to work they should all be the same version.

In the next update we should make sure that users can run multiple instances with different versions - we can use a system like Freemius and Action Scheduler use where the latest version is loaded.

Also adding a reference to this tool so we can use the same concept / idea: https://deliciousbrains.com/php-scoper-namespace-composer-depencies/