Add Quelea as a new project

[berry120]

I'm the lead developer of Quelea - we're always happy to welcome first timers and guide them through submitting their first PR 👍

ℹ️ Repository information

The repository has:

• [x] At least three issues with the good first issue label.
• [x] At least 10 contributors.
• [x] Detailed setup instructions for the project.
• [x] CONTRIBUTING.md
• [x] Actively maintained.