[TASK] Default active extension handling in package manager

Integrate the definition of packages that should be activated at
first installation and packages that are required for a minimal
usable system in the package manager.

There are now three possible properties in Classes/Package.php:

* protected - Package can not be uninstalled in em.
* partOfFactoryDefault - Package is activated at first installation.
* partOfMinimalUsableSystem - Package is activated if
  PackageStates.php is missing. extensionmanager and t3skin are
  affected here, if PackageStates.php is deleted, the install tool
  will create a new one with those packages activated, so the backend
  is "usable" enough to activate further packages.

Resolves: #53988
Releases: 6.2
Change-Id: I4f5d3f0a7d3bcf332d1e8e6c29156f93bae8029c
Reviewed-on: https://review.typo3.org/27226
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Thomas Maroschik
Tested-by: Thomas Maroschik
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring