provisioning: sketch out implementation

for now, this is completely unauthenticated

pkg/connector/connector.go

@@ -35,6 +35,7 @@ var _ bridgev2.NetworkConnector = (*DiscordConnector)(nil)
 func (d *DiscordConnector) Init(bridge *bridgev2.Bridge) {
 	d.Bridge = bridge
 	d.MsgConv = msgconv.NewMessageConverter(bridge, d.ReuploadMedia)
+	d.setUpProvisioningAPIs()
 }
 
 func (d *DiscordConnector) Start(ctx context.Context) error {