I made a complete editing pass plus another pass to see where I could add more links, both within the document and to other parts of Spring. The result was a thorough edit (though I'm sure I missed things, purely due to the size of the thing).
Move projects to better reflect the way that Spring Boot is released.
The following projects are under `spring-boot-project`:
- `spring-boot`
- `spring-boot-autoconfigure`
- `spring-boot-tools`
- `spring-boot-starters`
- `spring-boot-actuator`
- `spring-boot-actuator-autoconfigure`
- `spring-boot-test`
- `spring-boot-test-autoconfigure`
- `spring-boot-devtools`
- `spring-boot-cli`
- `spring-boot-docs`
See gh-9316
