Auto-generate the "Common application properties"

Prior to this commit, the application properties listed in the reference
documentation would be manually managed and updated.

This commit adds a new `spring-boot-configuration-docs` project that
extracts that information from the available JSON metadata and writes
Asciidoctor tables ready for inclusion in the reference documentation.

The `generateConfigurationPropertyTables.groovy` is using this library
and configures the sections and how namespaces should be organized.

Fixes gh-8237

spring-boot-project/spring-boot-docs/pom.xml

@@ -55,6 +55,11 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-loader-tools</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-configuration-docs</artifactId>
+			<version>${revision}</version>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-test</artifactId>
@@ -1244,6 +1249,7 @@
 								<script>file:///${project.basedir}/src/main/groovy/generateAutoConfigurationClassTables.groovy</script>
 								<script>file:///${project.basedir}/src/main/groovy/generateStarterTables.groovy</script>
 								<script>file:///${project.basedir}/src/main/groovy/generateTestSlicesTable.groovy</script>
+								<script>file:///${project.basedir}/src/main/groovy/generateConfigurationPropertyTables.groovy</script>
 							</scripts>
 						</configuration>
 						<dependencies>