replace Flight example with ToDo

[nmcl]

Check list:

Your pull request:

• [ ] targets the development branch
• [ ] uses the 999-SNAPSHOT version of Quarkus
• [ ] has tests (mvn clean test)
• [ ] works in native (mvn clean package -Pnative)
• [ ] has native tests (mvn clean verify -Pnative)
• [ ] makes sure the documentation must not be updated
• [ ] links the documentation update pull request (if needed)
• [ ] updates or creates the README.md file (with build and run instructions)
• [ ] For new quickstart, is located in the directory component-quickstart
• [ ] For new quickstart, is added to the root pom.xml and README.md