feat: initial setup for mentor platform 🧱

[tomas-salgado]

Description ✏️

This PR sets up a new app for mentor-platform, which functions alongside the member-profile app and the admin-dashboard app. Currently there is only an index page, but this PR contains all the rest of the set up and infra so that future PRs can focus on the functionality of the app itself.

Most of these files were just copied and modified from existing files related to set up in the other existing apps, in order to match the patterns.

Type of Change 🐞

• Feature - A non-breaking change which adds functionality.
• Fix - A non-breaking change which fixes an issue.
• Refactor - A change that neither fixes a bug nor adds a feature.
• Documentation - A change only to in-code or markdown documentation.
• Tests - A change that adds missing unit/integration tests.
• Chore - A change that is likely none of the above.

Checklist ✅

• I have done a self-review of my code.
• I have manually tested my code (if applicable).
• I have added/updated any relevant documentation (if applicable).