Change spring-boot-dependency-tools' parent to be spring-boot-dependencies

[wilkinsona]

spring-boot-dependency-tools currently uses spring-boot-tools as its parent. This means that it has spring-boot-parent in its hierarchy and its effective pom therefore contains spring-boot-parent's dependency management. From the perspective of providing versions to applications (in the CLI and in the Gradle plugin), this extra dependency management is unwanted and some runtime filtering is performed to remove it.

Updating the parent to be spring-boot-dependencies will remove the unwanted dependency management. This will mean that the filtering is no longer necessary and will make it easier to automatically document the versions that are provided.