Add an empty meson project

This allows to make keycodemapdb a subproject() in meson.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
diff --git a/meson.build b/meson.build
new file mode 100644
index 0000000..eb9416b
--- /dev/null
+++ b/meson.build
@@ -0,0 +1 @@
+project('keycodemapdb')