Add: Main app, main activity and navigation handling

app/src/main/java/dev/carlos/acronyms/viewmodel/NavigationViewmodel.kt

@@ -0,0 +1,18 @@
+package dev.carlos.acronyms.viewmodel
+
+import android.os.Bundle
+import androidx.annotation.IdRes
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import dev.carlos.core.navigation.NavigationEvent
+
+class NavigationViewmodel : ViewModel() {
+
+    val navigate = MutableLiveData<Pair<@IdRes Int, Bundle>>()
+
+    fun onNavigationEvent(event: NavigationEvent) {
+        when (event) {
+            else -> throw NoWhenBranchMatchedException("Undefined navigation event parent")
+        }
+    }
+}