Robo command to clone and scaffold subsites

[amitaibu]

This is another take without the complexity of git-submodules which is shown in #4

Disadvantage here is that git doesn't keep track of which subsites we had and which revision. On the other hand - and its a big one - we don't have to mess with git-submodules.

Instead Robo just git clones the sub-sites and with .gitignore we make sure the base repo doesn't get confused with those new repos.

Another improvement is that the robo is executed from ddev itself, and not the host, thus removing the need for the host to have latest PHP and extensions installed.
By running ddev auth ssh once, we're able to use git with the host credentials. So all that remains is:

ddev exec "cd .. && ./vendor/bin/robo fetch ./robo/sites-collection1.csv" && ddev restart

and cleanup:

ddev exec "cd .. && ./vendor/bin/robo reset"

Future Improvements

I can imagine adding in Robo some $this->ask("What is the Git URL?");, so sub-site owners could easily scaffold their new site.