Update gradle build to enable integration testing and smoother copying

roles/keycloak/files/providers/keycloak-mailpass-rest/build.gradle.kts

 plugins {
     java
+
+    id("org.unbroken-dome.test-sets") version "3.0.1"
+    id("com.adarshr.test-logger") version "2.1.1"
+}
+
+testSets {
+    create("integrationTest")
 }
 
 java {
@@ -13,15 +20,20 @@ version = "1.0.0"
 
 repositories {
     mavenCentral()
+
+    maven {
+        url = uri("https://dl.bintray.com/palantir/releases")
+    }
 }
 
 dependencies {
     val bouncyCastleVersion = "1.68"
+    val restassuredVersion = "4.3.3"
     val keycloakVersion = "12.0.1"
     val javaxVersion = "2.0.1.Final"
     val junitVersion = "4.13.1"
     val hamcrestVersion = "2.2"
-    val restassuredVersion = "4.3.3"
+    val dockerComposeRuleVersion = "1.5.0"
 
     implementation("org.bouncycastle:bcprov-jdk15on:$bouncyCastleVersion")
     implementation("io.rest-assured:rest-assured:$restassuredVersion")
@@ -35,6 +47,7 @@ dependencies {
 
     testImplementation("junit:junit:$junitVersion")
     testImplementation("org.hamcrest:hamcrest:$hamcrestVersion")
+    testCompile("com.palantir.docker.compose:docker-compose-rule-junit4:$dockerComposeRuleVersion")
 }
 
 tasks {
@@ -47,17 +60,21 @@ tasks {
         }
     }
 
-    wrapper {
-        gradleVersion = "6.7"
-    }
-
     test {
         useJUnit()
 
         testLogging {
             showStandardStreams = true
         }
-
-        maxHeapSize = "1G"
     }
 }
+
+tasks.named<Test>("integrationTest") {
+    useJUnit()
+}
+
+tasks.register<Copy>("copyJar") {
+    from(tasks.jar.get().outputs)
+    into("./docker")
+    into("./src/integrationTest/resources/docker")
+}