Move from java/ to kotlin/ directory

Android 12 dynamic color usage on login screen

app/src/main/kotlin/com/meloda/fast/io/Charsets.kt

@@ -0,0 +1,12 @@
+package com.meloda.fast.io
+
+import java.nio.charset.Charset
+import java.nio.charset.StandardCharsets
+
+object Charsets {
+
+    val ASCII: Charset = StandardCharsets.US_ASCII
+
+    val UTF_8: Charset = StandardCharsets.UTF_8
+
+}