Remove agent string

The agent string was inspired by the HTTP User-Agent header to serve as
a way to identify what's connecting to the cluster.  While there may
have been vision of other software connecting to a controller than the
Clusterio provided ones this seems highly unlikely to ever happen.

Remove redundant agent string for now.

packages/web_ui/src/components/HostViewPage.tsx

@@ -83,7 +83,6 @@ export default function HostViewPage() {
 			<Descriptions.Item label="Memory"><MetricMemoryUsed metrics={metrics} /></Descriptions.Item>
 			<Descriptions.Item label="Disk Usage"><MetricDiskRatio metrics={metrics} /></Descriptions.Item>
 			<Descriptions.Item label="Disk"><MetricDiskUsed metrics={metrics} /></Descriptions.Item>
-			<Descriptions.Item label="Agent">{host["agent"]}</Descriptions.Item>
 			<Descriptions.Item label="Version">{host["version"]}</Descriptions.Item>
 			{
 				host.tokenValidAfter

packages/web_ui/src/components/HostsPage.tsx

@@ -251,12 +251,6 @@ export default function HostsPage() {
 					render: (_, host) => <MetricDiskUsed metrics={metrics.get(host.id)} />,
 					hidden: !showNumbers,
 				},
-				{
-					title: "Agent",
-					dataIndex: "agent",
-					sorter: (a, b) => strcmp(a.agent, b.agent),
-					responsive: ["lg"],
-				},
 				{
 					title: "Version",
 					dataIndex: "version",

packages/web_ui/src/util/websocket.ts

@@ -30,7 +30,6 @@ export class ControlConnector extends lib.WebSocketClientConnector {
 			new lib.MessageRegisterControl(
 				new lib.RegisterControlData(
 					this.token,
-					"Clusterio Web UI",
 					packageJson.version,
 				)
 			)