[client,management] Feature/client service expose (#5411)

CLI: new expose command to publish a local port with flags for PIN, password, user groups, custom domain, name prefix and protocol (HTTP default).
Management/API: create/renew/stop expose sessions (streamed status), automatic naming/domain, TTL renewals, background expiration, new management RPCs and client methods.
UI/API: account settings now include peer_expose_enabled and peer_expose_groups; new activity codes for peer expose events.

management/internals/modules/reverseproxy/domain/manager/manager.go

@@ -221,6 +221,10 @@ func (m Manager) ValidateDomain(ctx context.Context, accountID, userID, domainID
 	}
 }
 
+func (m Manager) GetClusterDomains() []string {
+	return m.proxyURLAllowList()
+}
+
 // proxyURLAllowList retrieves a list of currently connected proxies and
 // their URLs
 func (m Manager) proxyURLAllowList() []string {