Merge pull request #7644 from piwik/config_step_2

Moby DIoC: Step 1 - Piwik environment encapsulation. List of all changes:

* introduction of Environment class that creates and encapsulates Piwik DI container
* introduction of concept of 'kernel global'. a kernel global is an object that cannot be overridden via the DI container, since it is used to create it.
* introduces three kernel objects: PluginList (describes which plugins are activated), GlobalSettingsProvider (provides global settings), and EnvironmentValidator (validates the environment)
* all environment validation logic was moved to EnvironmentValidator (tests added as well)
* removed ability to change Config files used by existing Config instance
* Moved Config::encodeValues/::decodeValues to IniFileChain
* Lots of hacks to test code
* removal of some useless CronArchive.php setup code
* small change to core\IP.php (fix to error silencing)
* added Plugin\Manager to DI container
* Removed cli-script-bootstrap.php (no longer used)