[!!!][TASK] Use typo3/contrib/vendor/ instead of Packages/

In a result of best practices with composer as well as taking
the tarball distributions (typo3_src.zip) into account, the
directory Packages/ is not necessarily optimal now for either
development and shipping a package.

Distributions (like the composer-installer for TYPO3) can still
use the Packages/ directory in their webroot for other
packages.

This means: The TYPO3 source will not contain any
third party library anymore in its GIT repository but instead
these are installed via composer.

For development purposes this means that a "composer install"
command will install all required dev-dependencies into
typo3/contrib/vendor/ which is now ignored by git and no
changes are installed anymore.

For the packaging process a "composer install --no-dev -o" will
be executed when building the tarball and zip files on each
release, downloading the necessary third-party libraries directly
into "typo3/contrib/vendor/".

Existing developer installations need to run
"rm -rf typo3/contrib/vendor/ bin/ Packages/Libraries/ composer.lock"
inside the typo3 repository directory and do a "composer install"
again after applying this patch.

This way, there is no conflict between autoloader as well as the
Packages/ directory anymore for the TYPO3 CMS Core.

The typo3/contrib/vendor/ folder is completely removed from
Git as it is now handled via composer.

Resolves: #66001
Releases: master
Change-Id: I70ff4e1427f2b9d888b7de336e577851116b93cf
Reviewed-on: http://review.typo3.org/38138


Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>