feat(rust): implement rust sled demo

Signed-off-by: hackerchai <i@hackerchai.com>

_rsdemo/sled/sled.go

@@ -0,0 +1,16 @@
+package sled
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/rust/sled"
+)
+
+func main() {
+	c.Printf(c.Str("helloworld\n"))
+	conf := &sled.SledConfig{}
+	conf.SetPath(c.Str("./db.sled"))
+	db := conf.OpenDB(conf)
+	db.Set(c.Str("key"), 3, c.Str("value"), 5)
+	value := db.Get(c.Str("key"), 3)
+	c.Printf(c.Str("value: %s\n"), value)
+}