lib/lsm6ds3_STdC: import 3rd party library

This is used by IMU on Control+ hub

Author: dlech

3RD_PARTY_NOTICES.md

@@ -80,6 +80,21 @@ subdirectories.
 - Conditions: License and copyright notice
 - Restrictions: Liability, warranty
 
+
+### STMems_Standard_C_drivers
+
+**path**: `lib/lsm6ds3tr_c_STdC/`
+
+**origin**: Git commit 5a189f9ccb81615c87d9ad2fb0f394cffb5853d6
+
+**url**: https://github.com/STMicroelectronics/STMems_Standard_C_drivers
+
+**terms**:
+- License: BSD-3-Clause
+- Permissions: Commercial use, distribution, modification, private use
+- Conditions: License and copyright notice
+- Restrictions: Liability, warranty
+
 ---
 
 Explanation of license terms can be found at <https://choosealicense.com/appendix/>.

lib/lsm6ds3tr_c_STdC/README.txt

@@ -0,0 +1,17 @@
+
+In the 'driver' folder there are the driver files of Mems Sensor (.h and .c)
+to be included in your project. 
+
+Driver documentation can be generate using Doxigen tool.
+
+The driver is platform independent, you need only to complete the two functions
+for write and read from Mems Hardware Bus.
+
+The files (.c) in 'example' folder, are examples showing how to integrate
+the Standard C driver in a project. They are written for STM32
+Microcontroller using CubeMX API, but you can use it as a guideline for
+every hardware.
+
+www.st.com/mems
+
+LSM6DS3TR-C DS rev3.0