doxygen: add groups for all modules

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/tcs3414cs/tcs3414cs.h

@@ -104,11 +104,17 @@ typedef struct {
     uint16_t clr;
 } tcs3414sc_rgb_t;
 
+/**
+ * @brief tcs3414cs color sensor library
+ * @defgroup tcs3414cs libupm-tcs3414cs
+ */
+
 /**
  * @brief C++ API for TCS3414CS chip (Color sensor)
  *
  * This file defines the TCS3414CS C++ interface for libtcs3414cs
  *
+ * @snippet tcs3414cs-example.cxx Interesting
  */
 class TCS3414CS {
     public: