[driver] Added vl53 ext submodule

Author: hshose

.gitmodules

@@ -52,3 +52,6 @@
 [submodule "ext/segger/rtt"]
 	path = ext/segger/rtt
 	url = git@github.com:modm-ext/segger-rtt.git
+[submodule "ext/vl53/vl53"]
+	path = ext/vl53/vl53
+	url = git@github.com:modm-ext/vl53-partial.git

README.md

@@ -871,8 +871,6 @@ your specific needs.
 <td align="center"><a href="https://modm.io/reference/module/modm-driver-touch2046">TOUCH2046</a></td>
 <td align="center"><a href="https://modm.io/reference/module/modm-driver-vl53l0">VL53L0</a></td>
 </tr><tr>
-<td align="center"><a href="https://modm.io/reference/module/modm-vl53-vl53l5cx">VL53L5CX</a></td>
-<td align="center"><a href="https://modm.io/reference/module/modm-vl53-vl53lmz">VL53L7/VL53L8</a></td>
 <td align="center"><a href="https://modm.io/reference/module/modm-driver-vl6180">VL6180</a></td>
 <td align="center"><a href="https://modm.io/reference/module/modm-driver-ws2812">WS2812</a></td>
 </tr>