change to Gradle file structure

sample_client/build.gradle

@@ -1,43 +1,15 @@
 apply plugin: 'com.android.application'
 
-repositories {
-    jcenter()
-}
-
 dependencies {
-    implementation project(':')
+    implementation project(':owncloudComLib')
 }
 
 android {
-    compileSdkVersion 26
+    compileSdkVersion 28
 
     defaultConfig {
         minSdkVersion 14
-        targetSdkVersion 26
-    }
-
-    sourceSets {
-        main {
-            manifest.srcFile 'AndroidManifest.xml'
-            java.srcDirs = ['src']
-            resources.srcDirs = ['src']
-            aidl.srcDirs = ['src']
-            renderscript.srcDirs = ['src']
-            res.srcDirs = ['res']
-            assets.srcDirs = ['assets']
-        }
-
-        // Move the tests to tests/java, tests/res, etc...
-        androidTest.setRoot('tests')
-
-        // Move the build types to build-types/<type>
-        // For instance, build-types/debug/java, build-types/debug/AndroidManifest.xml, ...
-        // This moves them out of them default location under src/<type>/... which would
-        // conflict with src/ being used by the main source set.
-        // Adding new build types or product flavors should be accompanied
-        // by a similar customization.
-        debug.setRoot('build-types/debug')
-        release.setRoot('build-types/release')
+        targetSdkVersion 28
     }
 
     lintOptions {
@@ -47,6 +19,7 @@ android {
     packagingOptions {
         exclude 'META-INF/LICENSE.txt'
     }
+    
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8