Externalize build properties.

See #1151.

Jenkinsfile

@@ -1,3 +1,9 @@
+def p = [:]
+node {
+    checkout scm
+    p = readProperties interpolate: true, file: 'ci/pipeline.properties'
+}
+
 pipeline {
 	agent none
 
@@ -12,7 +18,7 @@ pipeline {
 	}
 
 	stages {
-		stage("test: baseline (jdk17)") {
+		stage("test: baseline (Java 17)") {
 			when {
 				beforeAgent(true)
 				anyOf {
@@ -37,6 +43,10 @@ pipeline {
 							sh "docker login --username ${DOCKER_HUB_USR} --password ${DOCKER_HUB_PSW}"
 							sh "PROFILE=ci,all-dbs ci/test.sh"
 							sh "ci/clean.sh"
+						docker.image(p['docker.java.main.image']).inside(p['docker.java.inside.docker']) {
+							sh "docker login --username ${DOCKER_HUB_USR} --password ${DOCKER_HUB_PSW}"
+							sh "PROFILE=ci,all-dbs ci/test.sh"
+							sh "ci/clean.sh"
 						}
 					}
 				}
@@ -63,7 +73,7 @@ pipeline {
 			steps {
 				script {
 					docker.withRegistry('', 'hub.docker.com-springbuildmaster') {
-						docker.image('openjdk:17-bullseye').inside('-v $HOME:/tmp/jenkins-home') {
+						docker.image(p['docker.java.main.image']).inside(p['docker.java.inside.basic']) {
 							sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml -Pci,artifactory -Dmaven.repo.local=/tmp/jenkins-home/.m2/spring-data-jdbc-non-root ' +
 								'-Dartifactory.server=https://repo.spring.io ' +
 								"-Dartifactory.username=${ARTIFACTORY_USR} " +

ci/pipeline.properties

@@ -0,0 +1,24 @@
+# Java versions
+java.main.tag=8u312-b07-jdk
+java.next.tag=11.0.13_8-jdk
+java.lts.tag=17.0.1_12-jdk
+
+# Docker container images - standard
+docker.java.main.image=eclipse-temurin:${java.main.tag}
+docker.java.next.image=eclipse-temurin:${java.next.tag}
+docker.java.lts.image=eclipse-temurin:${java.lts.tag}
+
+# Supported versions of MongoDB
+docker.mongodb.4.0.version=4.0.23
+docker.mongodb.4.4.version=4.4.4
+docker.mongodb.5.0.version=5.0.3
+
+# Supported versions of Redis
+docker.redis.6.version=6.2.4
+
+# Supported versions of Cassandra
+docker.cassandra.3.version=3.11.10
+
+# Docker environment settings
+docker.java.inside.basic=-v $HOME:/tmp/jenkins-home
+docker.java.inside.docker=-u root -v /var/run/docker.sock:/var/run/docker.sock -v /usr/bin/docker:/usr/bin/docker -v $HOME:/tmp/jenkins-home