Introduce new TreeView UI component

Key highlights:

- Written from scratch to cater specifically to privacy.sexy's
  needs and requirements.
- The visual look mimics the previous component with minimal changes,
  but its internal code is completely rewritten.
- Lays groundwork for future functionalities like the "expand all"
  button a flat view mode as discussed in #158.
- Facilitates the transition to Vue 3 by omitting the Vue 2.0 dependent
  `liquour-tree` as part of #230.

Improvements and features:

- Caching for quicker node queries.
- Gradual rendering of nodes that introduces a noticable boost in
  performance, particularly during search/filtering.
  - `TreeView` solely governs the check states of branch nodes.

Changes:

- Keyboard interactions now alter the background color to highlight the
  focused item. Previously, it was changing the color of the text.
- Better state management with clear separation of concerns:
  - `TreeView` exclusively manages indeterminate states.
  - `TreeView` solely governs the check states of branch nodes.
  - Introduce transaction pattern to update state in batches to minimize
    amount of events handled.
- Improve keyboard focus, style background instead of foreground. Use
  hover/touch color on keyboard focus.
- `SelectableTree` has been removed. Instead, `TreeView` is now directly
  integrated with `ScriptsTree`.
- `ScriptsTree` has been refactored to incorporate hooks for clearer
  code and separation of duties.
- Adopt Vue-idiomatic bindings instead of keeping a reference of the
  tree component.
- Simplify and change filter event management.
- Abandon global styles in favor of class-scoped styles.
- Use global mixins with descriptive names to clarify indended
  functionality.

tests/unit/shared/Stubs/TreeNodeStub.ts

@@ -0,0 +1,35 @@
+import { HierarchyAccess } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/Hierarchy/HierarchyAccess';
+import { TreeNodeStateAccess } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/State/StateAccess';
+import { TreeNode } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode';
+import { NodeMetadataStub } from './NodeMetadataStub';
+import { HierarchyAccessStub } from './HierarchyAccessStub';
+
+export class TreeNodeStub implements TreeNode {
+  public state: TreeNodeStateAccess;
+
+  public hierarchy: HierarchyAccess = new HierarchyAccessStub();
+
+  public id: string;
+
+  public metadata?: object = new NodeMetadataStub();
+
+  public withMetadata(metadata: object): this {
+    this.metadata = metadata;
+    return this;
+  }
+
+  public withHierarchy(hierarchy: HierarchyAccess): this {
+    this.hierarchy = hierarchy;
+    return this;
+  }
+
+  public withState(state: TreeNodeStateAccess): this {
+    this.state = state;
+    return this;
+  }
+
+  public withId(id: string): this {
+    this.id = id;
+    return this;
+  }
+}