refactor public sharing backend to use frontend selection, rather than hard-wired frontend zids (#110)

controller/config.go

@@ -12,7 +12,6 @@ type Config struct {
 	V            int
 	Admin        *AdminConfig
 	Endpoint     *EndpointConfig
-	Proxy        *ProxyConfig
 	Email        *EmailConfig
 	Registration *RegistrationConfig
 	Store        *store.Config
@@ -30,11 +29,6 @@ type EndpointConfig struct {
 	Port int
 }
 
-type ProxyConfig struct {
-	UrlTemplate string
-	Identities  []string
-}
-
 type EmailConfig struct {
 	Host     string
 	Port     int