Docksal configuration improvements.

Improved the docksal configuration:

Added drushrc.php to container so that when you run fin drush uli it will tack the $VIRTUAL_HOST onto the URL
Changed the database connection injection (snippet in init command) to map to the db container internally
Automated the deletion / creation of the project containers.
Added hirak/prestissimo to the cli container to help speed up
Moved most code from the init command to init-site which can execute inside of the container with the #: exec_target = cli line
Modified all script variables to be wrapped in { } as to cause no possible confusion in bash variables.

ucdavis / sitefarm-distro-template