First draft of overview page for demos.

Signed-off-by: Ralph Lange <ralph.lange@de.bosch.com>

Author: ralph-lange

_data/docs.yml

@@ -56,6 +56,7 @@
 
 - title: Demos
   docs:
+   - tutorials/demos/overview
    - tutorials/demos/kobuki_demo
    - tutorials/demos/crazyflie_demo
    - tutorials/demos/tof_demo

_docs/tutorials/demos/kobuki_demo/index.md

@@ -2,7 +2,6 @@
 title: Kobuki Demo
 permalink: /docs/tutorials/demos/kobuki_demo/
 redirect_from:
-  - /docs/tutorials/demos/
   - /kobuki_demo/
 ---
 

_docs/tutorials/demos/overview/crazyflie.png

@@ -0,0 +1,17 @@
+---
+title: Overview
+permalink: /docs/tutorials/demos/overview/
+redirect_from:
+  - /docs/tutorials/demos/
+---
+
+In addition to the above tutorials, we created a collection of demos that showcase micro-ROS in real applications which are easy to reproduce by the community — and thus _you_. Unlike tutorials, we do not explain the demo code step by step, but provide ready-to-use Docker files to get you started as quickly as possible.
+
+Choose yourself:
+
+|              | [**Kobuki Demo**](../kobuki_demo) | [**Crazyflie Demo**](../crazyflie_demo) | [**ToF Sensor Demo**](../tof_demo) |
+| --- | :-: | :-: | :-: |
+| _RTOS_       | NuttX                             | FreeRTOS                                | Zephyr                             |
+| _Hardware_   | Kobuki, Olimex LTD STM32-E407     | Crazyflie, radio, flow deck             | ST B-L475E-IOT01A Discovery kit    |
+| _HW Costs_   | ≈ 360$                            | ≈ 330$                                  | ≈ 60$                              |
+|              | <img src="kobuki.png" style="margin:auto;"/> | <img src="crazyflie.png" style="margin:auto;"/> |                 |