add mppJsProject

mppJsProject.gradle

@@ -0,0 +1,32 @@
+project.version = "$version"
+project.group = "$group"
+
+// apply from: "$publishGradlePath"
+
+kotlin {
+    js (BOTH) {
+        browser()
+        nodejs()
+    }
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation kotlin('stdlib')
+                api "org.jetbrains.kotlinx:kotlinx-serialization-json:$kotlin_serialisation_core_version"
+            }
+        }
+        commonTest {
+            dependencies {
+                implementation kotlin('test-common')
+                implementation kotlin('test-annotations-common')
+            }
+        }
+        jsTest {
+            dependencies {
+                implementation kotlin('test-js')
+                implementation kotlin('test-junit')
+            }
+        }
+    }
+}