Feature: Add campaign title block

[pauloiankoski]

Resolves GIVE-1959

Description

This pull request lays the foundation for future Campaign-related blocks by introducing key structural elements. The updates in this PR include:

• Dynamic Webpack Entry: Automatically discovers all block directories and compiles them using their directory names.
• Dynamic Block Registration: Registers blocks dynamically based on their block.json files.
• Campaign Page REST API: Adds campaignId as a field to the REST API response for the Campaign Page CPT.
• Custom Hooks and Shared Components: Introduces reusable hooks and components to simplify campaign selection or retrieval from context within campaign blocks.
• Initial Campaign Title Block: Adds a basic Campaign Title block to serve as a reference and model for upcoming blocks.

These changes establish a scalable and flexible structure for Campaign blocks, enabling more streamlined development of future features.

Visuals

Testing Instructions

1. Test on a Campaign Page:

• Open a Campaign Page.
• Add the Campaign Title block.
• Verify that the block renders automatically, displaying the corresponding campaign title.

2. Test on Other Pages:

• Open any other page type (not a Campaign Page).
• Add the Campaign Title block.
• Ensure that a campaign selector is displayed.
• Select a campaign from the selector.
• Verify that the block updates and renders the title of the selected campaign.

Pre-review Checklist

• Acceptance criteria satisfied and marked in related issue
• Relevant @unreleased tags included in DocBlocks
• Includes unit tests
• Reviewed by the designer (if follows a design)
• Self Review of code and UX completed