Fix Network stack not being loaded (#26)

Due to the changes in the commit  
4c4ceb2, the Network Stack requires the use of a new Random Number Generator (RNG).
The UefiPayloadPkg has not been patched on default EDK2, since network implementation is not default in it. Therefore, the solution was to apply something that was done in another platforms in EDK2 adding the RngDxe and the Hash2DxeCrypto drivers (commits 3e72240 and e10d832).

UefiPayloadPkg/UefiPayloadPkg.dsc

@@ -855,6 +855,19 @@
   }
 !endif
 
+!if $(NETWORK_DRIVER_ENABLE) == TRUE
+  #
+  # Rng Protocol producer
+  #
+  SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf
+
+  #
+  # Hash2 Protocol producer
+  #
+  SecurityPkg/Hash2DxeCrypto/Hash2DxeCrypto.inf
+!endif
+
+
 !if $(SECURE_BOOT_ENABLE) == TRUE
   SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf
   UefiPayloadPkg/SecureBootEnrollDefaultKeys/SecureBootSetup.inf

UefiPayloadPkg/UefiPayloadPkg.fdf

@@ -389,6 +389,15 @@ INF MdeModulePkg/Application/BootManagerMenuApp/BootManagerMenuApp.inf
 #
 !if $(NETWORK_DRIVER_ENABLE) == TRUE
   !include NetworkPkg/Network.fdf.inc
+  #
+  # Rng Protocol producer
+  #
+  INF  SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf
+
+  #
+  # Hash2 Protocol producer
+  #
+  INF  SecurityPkg/Hash2DxeCrypto/Hash2DxeCrypto.inf
 !endif
 !endif