Rework webapp and deposit roles with and without reverse proxy

This now declares the following roles and deploys them accordingly (this does
not change anything in production):

• swh_rp_webapp: webapp with reverse proxy (deployed on node webapp0.azure)
• swh_rp_webapps: webapp and deposit with reverse proxy behavior (deployed on node moma)
• swh_webapp: only webapp service (deployed on node webapp.staging)
• swh_deposit: only deposit service (deploy on node deposit.staging)

Related to T2747