- Improve config system allowing a user customizable config_override.h file to ensure git pulls don't require merges

- Move DTU_RADIO_ID to config.h to allow for easy customization for multiple DTUs with non conflicting radio IDs

tools/esp8266/config.h

@@ -36,6 +36,9 @@
 #define DEF_RF24_CE_PIN         2
 #define DEF_RF24_IRQ_PIN        0
 
+// default radio ID
+#define DTU_RADIO_ID            ((uint64_t)0x1234567801ULL)
+
 // default NRF24 power, possible values (0 - 3)
 #define DEF_AMPLIFIERPOWER      2
 
@@ -96,4 +99,8 @@
 // changes the style of "/setup" page, visualized = nicer
 #define LIVEDATA_VISUALIZED
 
+#if __has_include("config_override.h")
+    #include "config_override.h"
+#endif
+
 #endif /*__CONFIG_H__*/