feat: lots of changes

- move demo-app to samples and rename demo-android
- rename yukireflection to yukireflection-core
- add demo-jvm in samples
- convert yukireflection-core from android to java-library
- optimize code
- other small changes

samples/demo-android/src/androidTest/java/com/highcapable/yukireflection/ExampleInstrumentedTest.kt

@@ -0,0 +1,24 @@
+package com.highcapable.yukireflection
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.highcapable.yukireflection", appContext.packageName)
+    }
+}