move projects and apps outisde of this repository

[2alin]

Description

We should use this repository only to host the landpage of my personal website.

At the moment, we have apps and projects in the following directories:

• ./apps/
  • update: content in this directory has been moved or removed
• ./learn/
• ./projects/
  • update: content in this directory has been moved or removed

We should move those directories to their repositories.

[2alin]

Update: apps that were in the ./apps/ folder have been moved to https://github.com/2alin/mini-apps