Added loading-bar exercise

loading-bar/go.mod

@@ -0,0 +1,3 @@
+module loading-bar
+
+go 1.22.0

loading-bar/main.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func main() {
+	for i := 0; i < 101; i++ {
+		fmt.Printf("\rLoading... %v%%", i)
+		time.Sleep(50 * time.Millisecond)
+	}
+	fmt.Printf("\n")
+}