Replace C++ with Cmake with GoLang gomobile

* Add ncsmsgo.arr which is the GoLang gomobile part
See: https://gitlab.com/nerzhul/ncsmsgo
* Android-NDK is not needed anymore
* Android app getVersion() now uses the Golang part
* Use the next getLastHTTPStatus() call in getVersion()
* Android app pushSms() now uses the Golang part
* JNI SmsBuffer has been replaced with GoLang aar bindings
-> This permits to remove some java code & increase performance
* Prepare a insecure switch flag to the Golang client

build.gradle

@@ -2,6 +2,7 @@ buildscript {
     repositories {
         mavenCentral()
         jcenter()
+        google()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.0.1'
@@ -47,11 +48,6 @@ android {
     packagingOptions {
         exclude  'META-INF/LICENSE.txt'
     }
-    externalNativeBuild {
-        cmake {
-            path 'CMakeLists.txt'
-        }
-    }
 }
 
 repositories {
@@ -69,4 +65,5 @@ dependencies {
     compile 'in.srain.cube:ultra-ptr:1.0.11'
     compile 'com.github.dmytrodanylyk.android-process-button:library:1.0.4'
     compile 'com.android.support:support-v4:27.0.2'
+    implementation project(':ncsmsgo')
 }