[TASK] Adds /Development/Packer/cookbooks folder

* this folder needs to be excluded because cookbooks are provided by "librarian-chef install" command
[TASK] Updates Packer template

* reformats code
* raises size of harddisk (not fixed-size harddisk)
* divide shell provisioner section
* adds chef-solo provisioner section
* adds initial chef-solo run_list
* shell provisioning
** update repos
* updates .gitignore while introducing Berkshelf
* adding Berkshelf (the way to go - instead of Librarian-Chef)
* updates Cheffile (until it gets deleted in near future)
* adds site-cookbook "environment"
[DOCUMENTATION] Adds mini Howto
[TASK] Updates Berksfile for use with Berkshelf >= 3.0.0

* updates also the packer template (chef-solo section)