Better modularize clipboard code (add "clip" package; break up TOTP code

clip/copyMOBILE.go

@@ -0,0 +1,16 @@
+//go:build (android && !termux) || ios
+
+package clip
+
+import (
+	"golang.design/x/clipboard"
+)
+
+// CopyString copies a string to the clipboard.
+func CopyString(continuous bool, copySubject string) error {
+	clipboard.Write(clipboard.FmtText, []byte(copySubject))
+	if !continuous {
+		LaunchClipClearProcess(copySubject)
+	}
+	return nil
+}