Enable plugin by default from Composer 2.2

Fix TypeError when configuration is invalid

Add compatibility with PHP-8.1

Add support for Composer-2 new events

Contains:

* Compatibilty with Composer 1.0
* Fix substitution with command abbreviation or alias

Extends compatibility to more versions of Composer

New Feature:

* Add support for substitutions by process
* Disable plugin for non supported versions of Composer
* Apply substitutions on Composer events too

Hotfix:

* Include missing files

Changes:

* Add support for substitutions by constants
* Add the 'escape' option
* Autoloading is not triggered anymore by callback of native functions
* Apply substitution only on invoked scripts

Contains:

* Fix scope isolation with IncludeProvider
* Fix issue #1 by calling autoloader when needed