Meira updates for bluetooth and audio (#2731)

* Add audio output

* Update Miera to fix bluetooth issues, bootloader definition.

* Added keymap with audio example

* Cleanup Meira audio code

keyboards/meira/config.h

@@ -35,11 +35,15 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* COL2ROW, ROW2COL, or CUSTOM_MATRIX */
 #define DIODE_DIRECTION CUSTOM_MATRIX
 
+#ifdef BACKLIGHT_ENABLE
 #define BACKLIGHT_LEVELS 10
 #define BACKLIGHT_PWM_MAP {2, 4, 8, 16, 40, 55, 70, 128, 200, 255}
+#endif
 
+#ifdef RGBLIGHT_ENABLE
 #define RGB_DI_PIN D3
 #define RGBLIGHT_TIMER
 #define RGBLED_NUM 15    // Number of LEDs
+#endif
 
 #endif