Use conventions instead of cross-project configuration

gradle userguide suggests to avoid allprojects/subprojects and use conventions instead

https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:convention_plugins_vs_cross_configuration

buildSrc/build.gradle

@@ -0,0 +1,3 @@
+plugins {
+    id 'groovy-gradle-plugin'
+}

buildSrc/src/main/groovy/brouter.application-conventions.gradle

@@ -0,0 +1,8 @@
+plugins {
+    id 'application'
+    id 'brouter.java-conventions'
+}
+
+application {
+    distTar.enabled = false
+}

buildSrc/src/main/groovy/brouter.java-conventions.gradle

@@ -0,0 +1,25 @@
+plugins {
+    id 'java'
+    id 'checkstyle'
+    id 'pmd'
+    id 'brouter.version-conventions'
+}
+
+group 'org.btools'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation 'junit:junit:4.13.2'
+}
+
+pmd {
+    consoleOutput = true
+    toolVersion = '7.0.0'
+    rulesMinimumPriority = 5
+    ruleSetFiles = files("${rootProject.rootDir}/config/pmd/pmd-ruleset.xml")
+    ruleSets = []
+    // ignoreFailures = true
+}

buildSrc/src/main/groovy/brouter.library-conventions.gradle

@@ -0,0 +1,21 @@
+plugins {
+    id 'java-library'
+    id 'maven-publish'
+    id 'brouter.java-conventions'
+}
+
+publishing {
+    repositories {
+        maven {
+            name = 'GitHubPackages'
+            url = uri("https://maven.pkg.github.com/$System.env.REPO")
+            credentials {
+                username = project.findProperty('gpr.user') ?: System.getenv('USERNAME')
+                password = project.findProperty('gpr.key') ?: System.getenv('TOKEN')
+            }
+        }
+    }
+    publications {
+        gpr(MavenPublication)
+    }
+}

buildSrc/src/main/groovy/brouter.version-conventions.gradle

@@ -0,0 +1,7 @@
+// NOTE:
+// there are four places to change the version number
+// this file
+// app: build.gradle (versionCode only)
+// OsmTrack (version and versionDate)
+// docs revisions.md (version and versionDate)
+version '1.7.3'