This change adds a new endpoint that uses the new project invite flow's
functionality instead of directly adding users to a project's members.
Issue: https://github.com/storj/storj/issues/5741
Change-Id: I6734f7e95be07086387fb133d6bdfd95e47cf4d9
During billing, before invoice creation, check if users are part of a
package plan. If so, and if the package plan is expired, remove unused
credit from the user's balance. If the user has credit in addition to
the package credit, send an analytics event to notify someone to handle
the credit removal manually.
Change-Id: Iad71d791f67c9733f9d9e42f962c64b2780264cc