Feature: add campaign page settings

[glaubersilva]

Resolves GIVE-1972

Description

This PR adds a new section in the campaign settings tab that allows users to enable or disable the campaign page. It also adds a button on the header that opens the campaign page in the WP block editor.

Affects

The campaign settings page.

Visuals

Testing Instructions

1. Open a campaign and go to the Settings tab;
2. Play around with the new options to enable or disable the campaign page.

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

[alaca]

Good job, @glaubersilva