Refactor: spec
Fix: don't override vagrant_dir to ensure the symlink we do to /vagrant_data will still work

cc @fh @gusano

Fixes: easybib/bibsample#41
Fix: support for multiple pools
Refactor: less hard-coding
Fix: add correct upstream name
Refactor: re-use partials, stuck duplicate code blocks into a loop
Fix: wrong partial name
Fix: set proper document_root and use alias
Refactor: duplicate code into a partial