packager.sh: renaming 'branch_id' vars to 'branch', add 'dep_' prefix to vars related to dependencies, add more sophisticated dependencies management
packager.sh: renaming 'branch_id' vars to 'branch', add 'dep_' prefix to vars related to dependencies, add more sophisticated dependencies management


Former-commit-id: bf496f1f35520c35d22113ef1c7e668e01e44bd2
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine