Bump dependencies to latest

Purge unused dependencies.

Update dependencies to latest except:

- ts-lint. Keep locked to 9.0.1 because that's the latest version that
  works with Webpack 4 that's still used by
  vue-cli-plugin-electron-builder.
- Keep eslint at version 7 because tests cannot be run/compiled with
  version 7, see eslint/eslint#15678, vuejs/vue-cli#6759.

Newer versions of ESLint modules do not allow linebreak after or before
= operator (operator-linebreak). This commit also changes files to
comply with it.

Closes #116, #119, #122, #130.

tests/unit/shared/Stubs/UserSelectionStub.ts

@@ -5,8 +5,8 @@ import { IEventSource } from '@/infrastructure/Events/IEventSource';
 import { EventSource } from '@/infrastructure/Events/EventSource';
 
 export class UserSelectionStub implements IUserSelection {
-  public readonly changed: IEventSource<readonly SelectedScript[]> =
-  new EventSource<readonly SelectedScript[]>();
+  public readonly changed: IEventSource<readonly SelectedScript[]> = new EventSource<
+  readonly SelectedScript[]>();
 
   public selectedScripts: readonly SelectedScript[] = [];