We're using the service.app.url incorrectly

[toban]

api url and then passing it down to the ui.

This introduces the services.app.apiUrl variable and uses that for the
urls that should point to the api instead.

[deer-wmde]

update: I did a rebase to fix this

Generally looks good to me but I get this (unrelated?) change in Terraform for staging if I run terraform plan with this branch checked out.

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # module.staging-buckets.google_storage_bucket.sql-backup will be updated in-place
  ~ resource "google_storage_bucket" "sql-backup" {
        id                          = "wikibase-dev-sql-backup"
        name                        = "wikibase-dev-sql-backup"
        # (11 unchanged attributes hidden)


      + retention_policy {
          + is_locked        = false
          + retention_period = 604700
        }
        # (1 unchanged block hidden)
    }