move montex to IDOBAO vendor folder (#15668)

* move montex to IDOBAO vendor folder

* move montex to montex/v1

keyboards/montex/readme.md → keyboards/idobao/montex/v1/readme.md

@@ -16,6 +16,6 @@ Then press the button labeled SW2 located between the 2 upper LEDs.
 
 Make example for this keyboard (after setting up your build environment):
 
-    make montex:default
+    make idobao/montex/v1:default
 
 See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).

keyboards/montex/montex.c → keyboards/idobao/montex/v1/v1.c

@@ -14,4 +14,4 @@
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include "montex.h"
+#include "v1.h"