Relocate projects to spring-boot-project

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

spring-boot-project/spring-boot-devtools/src/test/resources/org/springframework/boot/devtools/restart/classloader/Parent.txt

@@ -0,0 +1 @@
+fromparent

spring-boot-project/spring-boot-devtools/src/test/resources/org/springframework/boot/devtools/settings/spring-devtools-exclude.properties

@@ -0,0 +1,2 @@
+restart.exclude.a=a.*
+restart.exclude.b=b.*

spring-boot-project/spring-boot-devtools/src/test/resources/org/springframework/boot/devtools/settings/spring-devtools-include.properties

@@ -0,0 +1,2 @@
+restart.include.a=a.*
+restart.include.b=b.*

spring-boot-project/spring-boot-devtools/src/test/resources/user-home/.spring-boot-devtools.properties

@@ -0,0 +1 @@
+spring.thymeleaf.cache=true