Create new templates of ubuntu
Add configuration of "http_directory" in vitrualbox.json
* ssh_wait_timeout
   * 10m is too long. so modified "5m"
* boot_command
   * I want to see the process in which boot_command has a first element
Modify ssh configurations
* enable to export virtual_box
* unify the ssh_username to "packer", and ssh_password to "packer"
* Username and Password unify 'vagrant' because of using Vagrant
* Add 'post-processors' configuration to virtualbox.json
   * For the purpose of output to .box extnames
* Add 'provisioners' configuration to virtualbox.json for the ssh connection
   * enable to 'curl' command for setup_ssh.sh
* Add base.sh for setup sudoers and others
* Add configurations of apt-installs for Ruby, guest additions, and so on
* Remove pkgsel/include settings of installing curl because of adding to install 'curl' with apt-install
* Add execute_command configuration to virtualbox.json for sudoers command execution
* Add provisioner shellscript of setup ssh configurations