Refactor fat jar loader classes so that less `char[]` instances are
created. This is primarily achieved by adding a new `StringSequence`
class that can chop up Strings without needing to copy the underlying
array. Since Java 8, calls to `String.subString(...)` always copy the
underlying char array. For many of the operations that we need, this
is unnecessary.
Fixes gh-11405
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
