Fixing Singleton typing to correctly return child class (#1914)

- Add distinction between `getInstance` and `getInstanceOrCreate` since
  it is not always possible to create an instance (since you might not
  know the correct arguments)

- Remove all the `export const *Store = *Store.getInstance<*Store>();`
  calls as it defeats the purpose of `Singleton`. Plus with the typing
  changes the appropriate `*Store.getInstance()` is "short enough".

- Special case the two extension export facades to not need to use
  `getInstanceOrCreate`. Plus since they are just facades it is always
  possible to create them.

- Move some other types to be also `Singleton`'s: ExtensionLoader,
  ExtensionDiscovery, ThemeStore, LocalizationStore, ...

- Fixed dev-run always using the same port with electron inspect

- Update Store documentation with new recommendations about creating
  instances of singletons

- Fix all unit tests to create their dependent singletons

Signed-off-by: Sebastian Malton <sebastian@malton.name>

src/renderer/components/+nodes/node-charts.tsx

@@ -6,7 +6,7 @@ import { NoMetrics } from "../resource-metrics/no-metrics";
 import { IResourceMetricsValue, ResourceMetricsContext } from "../resource-metrics";
 import { observer } from "mobx-react";
 import { ChartOptions, ChartPoint } from "chart.js";
-import { themeStore } from "../../theme.store";
+import { ThemeStore } from "../../theme.store";
 import { mapValues } from "lodash";
 
 type IContext = IResourceMetricsValue<Node, { metrics: IClusterMetrics }>;
@@ -14,7 +14,7 @@ type IContext = IResourceMetricsValue<Node, { metrics: IClusterMetrics }>;
 export const NodeCharts = observer(() => {
   const { params: { metrics }, tabId, object } = useContext<IContext>(ResourceMetricsContext);
   const id = object.getId();
-  const { chartCapacityColor } = themeStore.activeTheme.colors;
+  const { chartCapacityColor } = ThemeStore.getInstance().activeTheme.colors;
 
   if (!metrics) {
     return null;

src/renderer/components/+nodes/node-details.tsx

@@ -18,7 +18,7 @@ import { KubeObjectMeta } from "../kube-object/kube-object-meta";
 import { KubeEventDetails } from "../+events/kube-event-details";
 import { kubeObjectDetailRegistry } from "../../api/kube-object-detail-registry";
 import { ResourceType } from "../cluster-settings/components/cluster-metrics-setting";
-import { clusterStore } from "../../../common/cluster-store";
+import { ClusterStore } from "../../../common/cluster-store";
 
 interface Props extends KubeObjectDetailsProps<Node> {
 }
@@ -54,7 +54,7 @@ export class NodeDetails extends React.Component<Props> {
       "Disk",
       "Pods",
     ];
-    const isMetricHidden = clusterStore.isMetricHidden(ResourceType.Node);
+    const isMetricHidden = ClusterStore.getInstance().isMetricHidden(ResourceType.Node);
 
     return (
       <div className="NodeDetails">