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- Remove `Cluster.ownerRef` as it is outdated and no longer needed for 5.0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/cluster-detectors/base-cluster-detector.ts

@@ -1,5 +1,6 @@
-import request, { RequestPromiseOptions } from "request-promise-native";
+import { RequestPromiseOptions } from "request-promise-native";
 import { Cluster } from "../cluster";
+import { k8sRequest } from "../k8s-request";
 
 export type ClusterDetectionResult = {
   value: string | number | boolean
@@ -7,11 +8,9 @@ export type ClusterDetectionResult = {
 };
 
 export class BaseClusterDetector {
-  cluster: Cluster;
   key: string;
 
-  constructor(cluster: Cluster) {
-    this.cluster = cluster;
+  constructor(public cluster: Cluster) {
   }
 
   detect(): Promise<ClusterDetectionResult> {
@@ -19,16 +18,6 @@ export class BaseClusterDetector {
   }
 
   protected async k8sRequest<T = any>(path: string, options: RequestPromiseOptions = {}): Promise<T> {
-    const apiUrl = this.cluster.kubeProxyUrl + path;
-
-    return request(apiUrl, {
-      json: true,
-      timeout: 30000,
-      ...options,
-      headers: {
-        Host: `${this.cluster.id}.${new URL(this.cluster.kubeProxyUrl).host}`, // required in ClusterManager.getClusterForRequest()
-        ...(options.headers || {}),
-      },
-    });
+    return k8sRequest(this.cluster, path, options);
   }
 }