Update toolchain; remove gradle

.gitignore

@@ -1,6 +1,9 @@
 .DS_Store
 
 .gradle
+gradlew
+gradlew.bat
+gradle/
 build
 .idea
 topic-backlog-expert-level.iml

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "license-copyright"]
 	path = license-copyright
 	url = https://github.com/isaqb-org/license-copyright
+[submodule "gradle-tools"]
+	path = gradle-tools
+	url = https://github.com/isaqb-org/gradle-tools

README.adoc

@@ -33,10 +33,7 @@ Create an issue, a merge- or pull-request
 == How to build the documents
 Prerequisite: You need a Java Runtime(tm) installed.
 
-You build the output documents with gradle:
-[source,console]
-$ ./gradlew buildDocs
-
+You build the output documents with gradle: `./gradle-tools/gradlew buildDocs`
 That will produce both pdf and html output in German (DE) _and_ English (EN), unless you modify the configuration.
 
 In case you want to change that, adjust the following part of `build.gradle`:

build.gradle

@@ -1,42 +1,6 @@
-import java.text.SimpleDateFormat
-
-plugins {
-    id "java"
-    id "application"
-}
-
-def group = "org.isaqb"
-def releaseVersion = System.getenv("RELEASE_VERSION")
-def localVersion = "LocalBuild"
-project.version = releaseVersion == null ? localVersion : releaseVersion
-def curriculumFileName = "topic-backlog-expert-level"
-def versionDate = new SimpleDateFormat("yyyyMMdd").format(new Date())
-def languages = ["DE", "EN"]
-
-repositories {
-    mavenCentral()
-}
-
-dependencies {
-    implementation("org.asciidoctor:asciidoctorj:2.5.10")
-    implementation("org.asciidoctor:asciidoctorj-pdf:2.3.9")
-}
-
-application {
-    mainClass.set("org.isaqb.asciidoc.Main")
-    applicationDefaultJvmArgs = [
-        """-DprojectVersion=${project.version}""",
-        """-DcurriculumFileName=${curriculumFileName}""",
-        """-DversionDate=${versionDate}""",
-        """-Dlanguages=${languages.join(',')}""",
-        """--add-opens""", """java.base/sun.nio.ch=ALL-UNNAMED""",
-        """--add-opens""", """java.base/java.io=ALL-UNNAMED"""]
-}
-
-tasks.register('buildDocs') {
-    description = 'Grouping task for generating all languages in several formats'
-    group = 'documentation'
-    dependsOn "run"
+ext {
+    curriculumFileName = "curriculum-foundation"
+    languages = ["DE", "EN"]
 }
 
-defaultTasks "buildDocs"
+defaultTasks 'buildDocs'