Improve co-existence of usermods sharing I2C

Improve co-existence of several popular usermods with respect to shared I2C bus.
- ensure that i2c_sda and i2c_scl are used when defined
- ensure that HW_PIN_SDA / HW_PIN_SCL are not overwritten
- ensure that Wire.begin()nis always called with user-defined pins (remove rogue Wire.begin() without parameters)
- ensure that set.cpp / cfg.cpp use esp32-specific global Wire objects.

usermods/usermod_v2_four_line_display_ALT/usermod_v2_four_line_display_ALT.h

@@ -1,5 +1,10 @@
 #pragma once
 
+#include <Arduino.h>              // WLEDMM: make sure that I2C drivers have the "right" Wire Object
+#include <Wire.h>
+#undef U8X8_NO_HW_I2C             // WLEDMM: we do want I2C hardware drivers - if possible
+//#define WIRE_INTERFACES_COUNT 2   // experimental - tell U8x8Lib that there is a econd Wire unit
+
 #include "wled.h"
 #include <U8x8lib.h> // from https://github.com/olikraus/u8g2/
 #include "4LD_wled_fonts.c"