Merge php and nginx deployments, Remove drush build components and reuse php

• Merges PHP and Nginx deployment configs into a single deployment config using side-cars -> Closes #25 (closed)
• Removes drush build components, in order to use php image for tooling -> Closes #https://gitlab.cern.ch/webservices/webframeworks-planning/-/issues/244
• Remove site-builder-base imagestream locally and it's dependencies -> Closes #33 (closed)