add README.md to SickLaserUnit for better documentation of setup

source/RobotAPI/drivers/SickLaserUnit/README.md

+# SickLaserUnit
+Armarx adapter to the SICK laser scanner driver
+
+Uses the sick_scan_base driver to communicate with the SICK_TiM571 Laser Scanners installed in Armar-DE and translates their timestamps and data to ArmarX types.
+After conversion, the scan data is published to the configured topic.
+
+
+## Installation
+
+1. Download and build the sick_scan_base project from https://github.com/SICKAG/sick_scan_base
+   ```console
+   git clone https://github.com/SICKAG/sick_scan_base.git
+
+   cd sick_scan_base
+   mkdir -p ./build
+   cd ./build
+   cmake .. && make
+   ```
+
+2. The package uses the script RobotAPI/etc/cmake/Findsick_scan_base.cmake to link against the sick drivers.
+   For this to work, the CMake variable sick_scan_base_DIR must be set to the path where the driver has been downloaded to.
+
+3. Build this package and configure its parameters to match the Laser Scanner setup.
+
+## Runnig
+
+To use the package, make sure your LaserScanners are connected to the PC and the configured IP addresses match the ones set by the SOPAS tool.
+
+You can use ping to check whether the scanners are connected.
+```console
+ping 192.168.8.133
+```
+