Add support of unified provisioning to Arduino

1. WiFiProv.ino sketch is added that allows arduino users to do provisioning via SoftAP or BLE. WiFi.beginProvision( ) API is designed for provisioning in Arduino.
2. In WiFiProv.h provisioning class is defined.
3. WiFiProv.cpp contains implementation for provisioning class.
4. README.md file is added which contains detail information for working.

libraries/WiFi/src/WiFiProv.h

@@ -0,0 +1,55 @@
+/*
+    WiFiProv.h - Base class for provisioning support
+    All right reserved.
+ 
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+  
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+  
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include "wifi_provisioning/manager.h"
+#include "wifi_provisioning/scheme_ble.h"
+#include "esp_wifi.h"
+#include "nvs_flash.h"
+#include "SimpleBLE.h"
+//Select the scheme using which you want to provision
+enum scheme
+{
+    WIFI_PROV_SCHEME_BLE,
+    WIFI_PROV_SCHEME_SOFTAP,
+    WIFI_PROV_SCHEME_CONSOLE
+};
+//Provisioning class 
+class WiFiProvClass
+{
+    protected:
+        static bool prov_enable;
+  
+    public:
+        WiFiProvClass() {
+            prov_enable = false;
+        }
+
+        bool isProvEnabled();
+    
+        void beginProvision(scheme prov_scheme = WIFI_PROV_SCHEME_SOFTAP, wifi_prov_event_handler_t scheme_event_handler = WIFI_PROV_EVENT_HANDLER_NONE, wifi_prov_security_t security = WIFI_PROV_SECURITY_1, const char * pop = "abcd1234", const char * service_name = NULL, const char * service_key = NULL, uint8_t *uuid = NULL);
+};
+
+/*
+ Event Handler for BLE
+      - WIFI_PROV_SCHEME_BLE_EVENT_HANDLER_FREE_BTDM
+      - WIFI_PROV_SCHEME_BLE_EVENT_HANDLER_FREE_BLE
+      - WIFI_PROV_SCHEME_BLE_EVENT_HANDLER_FREE_BT
+Event Handler for SOFTAP
+      - WIFI_PROV_EVENT_HANDLER_NONE
+*/