Fix kubeconfig-sync issues (#2692)

- Removed `getFreePort` as its use is always a race condition. Change
  all uses of it to retrive the port after listening

- Added `getPortFrom` as a helper function to read a port from a stream

- Remove `Cluster.ownerRef` as it is outdated and no longer needed for 5.0

- Remove `Cluster.enabled`, no longer needed because of above

- Removed `Cluster.init`, moved its contents into `Cluster.constructor`
  as nothing in that function is asyncronous. Currently only being run
  on `main` as a stop gap until `renderer` gets its own version of
  `Cluster`

- Refactored `LensProxy` so as to prevent `pty.node` (a NodeJS
  extension) being included in `webpack.extension.ts`'s run

- Removed the passing around of the proxy port as that can now be
  accessed from an instance of `LensProxy`

- purge ContextHandler's cache on disconnect

Co-authored-by: Sebastian Malton <sebastian@malton.name>

src/main/utils/get-port.ts

@@ -0,0 +1,51 @@
+import { Readable } from "stream";
+import URLParse from "url-parse";
+
+interface GetPortArgs {
+  /**
+   * Should be case insensitive
+   * Must have a named matching group called `address`
+   */
+  lineRegex: RegExp;
+  /**
+   * Called when the port is found
+   */
+  onFind?: () => void;
+  /**
+   * Timeout for how long to wait for the port.
+   * Default: 5s
+   */
+  timeout?: number;
+}
+
+/**
+ * Parse lines from `stream` (assumes data comes in lines) to find the port
+ * which the source of the stream is watching on.
+ * @param stream A readable stream to match lines against
+ * @param args The args concerning the stream
+ * @returns A Promise for port number
+ */
+export function getPortFrom(stream: Readable, args: GetPortArgs): Promise<number> {
+  return new Promise<number>((resolve, reject) => {
+    const handler = (data: any) => {
+      const logItem: string = data.toString();
+      const match = logItem.match(args.lineRegex);
+
+      if (match) {
+        // use unknown protocol so that there is no default port
+        const addr = new URLParse(`s://${match.groups.address.trim()}`);
+
+        args.onFind?.();
+        stream.off("data", handler);
+        clearTimeout(timeoutID);
+        resolve(+addr.port);
+      }
+    };
+    const timeoutID = setTimeout(() => {
+      stream.off("data", handler);
+      reject(new Error("failed to retrieve port from stream"));
+    }, args.timeout ?? 5000);
+
+    stream.on("data", handler);
+  });
+}