Add About Page with Reusable Components

[demilade111]

Description:
This PR introduces the About page, featuring reusable components to enhance consistency across the application. The key additions include:

• AboutHero: Serves as the main header for the About page.
• MissionSection: Highlights the club's mission.
• ValuesSection: Showcases the club's core values.
• ExecutiveDialog: Displays detailed information about executives.
• ExecutiveMemberProfileList: Lists executive profiles.
• ExecutiveMemberProfileCard: Represents individual executive profiles.

Additionally, the following updates were made:

• State Management: Implemented executiveStore using Zustand for managing executive data with persistence.
• Routing: Updated App.tsx to include routing for the new About page.
• Styling: Added gradient styles in index.css for consistent theming on the About page.
• Environment Configuration: Configured environment variables in .env for API base URL management.

**Additional Information:**
- The `.env` file has been added to `.gitignore` to protect sensitive information.
- Ensure that the environment variable `VITE_BASE_URL` is set in your `.env` file as follows:

VITE_BASE_URL=''

This variable sets the base URL for API requests related to executive data. Ensure the `.env` file is located in the root directory of your project. After adding the variable, restart your development server to apply the changes.

This PR enhances the application's structure by introducing modular components for the About page, facilitating easier maintenance and future updates.