Optimize configuration of project repositories

This change applies repository content filtering to configured
repositories, reducing the time spent during dependency resolution.

This fixes an issue where requests for 'org.opensaml',
'net.shibboleth.utilities' and 'net.minidev' dependencies were being
made in the Spring releases repositories, resulting in many failed
requests during dependency resolution and increased resolution times.

Closes gh-13582

docs/spring-security-docs.gradle

@@ -1,6 +1,7 @@
 plugins {
 	id 'org.antora' version '1.0.0'
 	id 'io.spring.antora.generate-antora-yml' version '0.0.1'
+	id 'io.spring.convention.repository'
 }
 
 apply plugin: 'io.spring.convention.docs'
@@ -59,10 +60,3 @@ def resolvedVersions(Configuration configuration) {
 				.resolvedArtifacts
 				.collectEntries { [(it.name + '-version'): it.moduleVersion.id.version] }
 }
-
-repositories {
-	mavenCentral()
-	maven { url 'https://repo.spring.io/release' }
-	maven { url 'https://repo.spring.io/milestone' }
-	maven { url 'https://repo.spring.io/snapshot' }
-}