Certificate/wireless plugins; major refactoring

Migrate much of BI to Services.
Added Wireless Profile Provider plugin feature.
Added Certificate Authority Provider plugin feature.
Modified Certificate Provider plugin feature.
Database migration v17, for Device Profiles.
Enrolment Client Updated to support CA Certificates, Wireless Profiles
and Hardware Info.
New Client Enrolment Protocol to support new features.
Plugin Manifest Generator added to main solution.
Improved AD search performance.

Disco.Client/Interop/Native/WLAN_INTERFACE_INFO.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Disco.Client.Interop.Native
+{
+    /// <summary >
+    /// The WLAN_INTERFACE_INFO structure contains information about a wireless LAN interface.
+    /// </summary >
+    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+    public struct WLAN_INTERFACE_INFO
+    {
+        /// <summary>
+        /// Contains the GUID of the interface.
+        /// </summary>
+        public Guid InterfaceGuid;
+
+        /// <summary>
+        /// Contains the description of the interface.
+        /// </summary>
+        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
+        public string strInterfaceDescription;
+
+        /// <summary>
+        /// Contains a WLAN_INTERFACE_STATE value that indicates the current state of the interface.
+        /// Windows XP with SP3 and Wireless LAN API for Windows XP with SP2:  Only the wlan_interface_state_connected,
+        ///   wlan_interface_state_disconnected, and wlan_interface_state_authenticating values are supported.
+        /// </summary>
+        public WLAN_INTERFACE_STATE isState;
+    }
+}