meson: replace create-config with meson configure_file

Move the create-config logic to meson.build; create a
configuration_data object and let meson handle the
quoting and output.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/block.c b/block.c
index 67c5028..2ba76b2 100644
--- a/block.c
+++ b/block.c
@@ -433,9 +433,11 @@
 {
     static const char *whitelist_rw[] = {
         CONFIG_BDRV_RW_WHITELIST
+        NULL
     };
     static const char *whitelist_ro[] = {
         CONFIG_BDRV_RO_WHITELIST
+        NULL
     };
     const char **p;