Add vm.overrides property in pipewire and pulse-server

Apply vm.override properties when running in a VM. Increase the
default quantum to 1024 when running in a VM to cause less
dropouts.

src/daemon/pipewire-pulse.conf.in

@@ -43,6 +43,10 @@ context.modules = [
 	    #pulse.min.quantum = 256/48000          # 5ms
 	    #pulse.default.format = F32
 	    #pulse.default.position = [ FL FR ]
+            # These overrides are only applied when running in a vm.
+            vm.overrides = {
+	        pulse.min.quantum = 1024/48000         # 22ms
+            }
         }
     }
 ]