New srverrors package added. New error handling added to control package

internal/server/srverrors/error.go

@@ -0,0 +1,19 @@
+package srverrors
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+type ServerErrMessage struct {
+	Reason string
+}
+
+func WriteErrorResponse(statusCode int, reasonMsg string, res http.ResponseWriter) {
+	respBody := ServerErrMessage{}
+	respBody.Reason = reasonMsg
+	bb, _ := json.Marshal(respBody)
+	res.Header().Add("Content-Type", "application/json; charset=utf-8")
+	res.WriteHeader(statusCode)
+	_, _ = res.Write(bb)
+}