Make all clients of swh-storage use origin URL as identifier and use visit types instead of origin types

Two different changes to do, but they syntactically are close to each other, so I'm making a single task

• swh-indexer: swh-indexer!180 (closed)
• loaders:
  • swh-loader-core swh-loader-core!27 (closed)
  • swh-loader-git: swh-loader-git!20 (closed)
  • swh-loader-mercurial swh-loader-mercurial!12 (closed)
  • swh-loader-npm swh-loader-npm!6 (closed)
  • swh-loader-pypi swh-loader-pypi!22 (closed)
  • swh-loader-svn swh-loader-svn!13 (closed)
• swh-lister swh-lister!71 (closed)
• swh-web: swh-web#1805 swh-web!144 (closed) swh-web!145 (closed) swh-web!993 (closed)

---

Migrated from T1816 (view on Phabricator)