Auto-generate AndroidManifest.xml (#112)

Relates to: #109

I'm not sure if this is strictly necessary anymore because once I had it
done, I realized that #72 has stripped the `reactnative` prefix from the
package name again. So technically UBRN's current output should work
with what create-react-native-library generates without this change
applied. It might not hurt either way though?

crates/ubrn_cli/src/android.rs

@@ -88,6 +88,10 @@ impl AndroidConfig {
         self.directory(project_root).join(&self.jni_libs)
     }
 
+    fn main_src(&self) -> String {
+        "src/main".to_string()
+    }
+
     fn java_src(&self) -> String {
         "src/main/java".to_string()
     }
@@ -96,6 +100,10 @@ impl AndroidConfig {
         self.package_name.clone()
     }
 
+    pub(crate) fn src_main_dir(&self, project_root: &Utf8Path) -> Utf8PathBuf {
+        self.directory(project_root).join(self.main_src())
+    }
+
     pub(crate) fn src_main_java_dir(&self, project_root: &Utf8Path) -> Utf8PathBuf {
         self.directory(project_root).join(self.java_src())
     }

crates/ubrn_cli/src/codegen/mod.rs

@@ -160,6 +160,7 @@ mod files {
             BuildGradle::rc_new(config.clone()),
             CMakeLists::rc_new(config.clone()),
             CppAdapter::rc_new(config.clone()),
+            AndroidManifest::rc_new(config.clone()),
             // iOS
             ModuleTemplateH::rc_new(config.clone()),
             ModuleTemplateMm::rc_new(config.clone()),
@@ -295,6 +296,18 @@ mod files {
             project_root.join(filename)
         }
     }
+
+    templated_file!(AndroidManifest, "AndroidManifest.xml");
+    impl RenderedFile for AndroidManifest {
+        fn path(&self, project_root: &Utf8Path) -> Utf8PathBuf {
+            let filename = "AndroidManifest.xml";
+            self.config
+                .project
+                .android
+                .src_main_dir(project_root)
+                .join(filename)
+        }
+    }
 }
 
 #[cfg(test)]

crates/ubrn_cli/src/codegen/templates/AndroidManifest.xml

@@ -0,0 +1,5 @@
+{%- let android = self.config.project.android.clone() %}
+<!-- Generated by uniffi-bindgen-react-native -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="{{ android.package_name() }}">
+</manifest>