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/+apps-releases/release-details.tsx

@@ -19,7 +19,7 @@ import { Button } from "../button";
 import { releaseStore } from "./release.store";
 import { Notifications } from "../notifications";
 import { createUpgradeChartTab } from "../dock/upgrade-chart.store";
-import { themeStore } from "../../theme.store";
+import { ThemeStore } from "../../theme.store";
 import { apiManager } from "../../api/api-manager";
 import { SubTitle } from "../layout/sub-title";
 import { secretsStore } from "../+config-secrets/secrets.store";
@@ -259,7 +259,7 @@ export class ReleaseDetails extends Component<Props> {
 
     return (
       <Drawer
-        className={cssNames("ReleaseDetails", themeStore.activeTheme.type)}
+        className={cssNames("ReleaseDetails", ThemeStore.getInstance().activeTheme.type)}
         usePortal={true}
         open={!!release}
         title={title}