Make Arduino_DebugUtils optional

[pennam]

If Arduino_DebugUtils is included in the Sketch or in other libraries this library will follow the debug rules configured, otherwise Arduino_DebugUtils is not included and debug is disabled.

Fixes #47

[github-actions]

Memory usage change @ 48e8c8d

Board	flash	%	RAM for global variables	%
arduino:mbed:envie_m7	💚 -816 - 0	-0.1 - 0.0	💚 -24 - 0	-0.0 - 0.0
arduino:mbed_giga:giga	💚 -824 - 0	-0.04 - 0.0	💚 -8 - 0	-0.0 - 0.0
arduino:mbed_nicla:nicla_vision	💚 -824 - 0	-0.04 - 0.0	💚 -8 - 0	-0.0 - 0.0
arduino:mbed_opta:opta	💚 -816 - 0	-0.04 - 0.0	💚 -40 - 0	-0.01 - 0.0

Click for full report table

Board	examples/OTA_Qspi_Flash flash	%	examples/OTA_Qspi_Flash RAM for global variables	%	examples/OTA_Qspi_Flash_Ethernet flash	%	examples/OTA_Qspi_Flash_Ethernet RAM for global variables	%	examples/OTA_SD_Portenta flash	%	examples/OTA_SD_Portenta RAM for global variables	%	examples/OTA_Usage_Portenta flash	%	examples/OTA_Usage_Portenta RAM for global variables	%
arduino:mbed:envie_m7	-752	-0.1	-16	-0.0	-816	-0.1	-24	-0.0	-816	-0.1	-16	-0.0	0	0.0	0	0.0
arduino:mbed_giga:giga	-824	-0.04	-8	-0.0									0	0.0	0	0.0
arduino:mbed_nicla:nicla_vision	-824	-0.04	-8	-0.0									0	0.0	0	0.0
arduino:mbed_opta:opta	-816	-0.04	-32	-0.01	-760	-0.04	-40	-0.01					0	0.0	0	0.0

Click for full report CSV

Board,examples/OTA_Qspi_Flash<br>flash,%,examples/OTA_Qspi_Flash<br>RAM for global variables,%,examples/OTA_Qspi_Flash_Ethernet<br>flash,%,examples/OTA_Qspi_Flash_Ethernet<br>RAM for global variables,%,examples/OTA_SD_Portenta<br>flash,%,examples/OTA_SD_Portenta<br>RAM for global variables,%,examples/OTA_Usage_Portenta<br>flash,%,examples/OTA_Usage_Portenta<br>RAM for global variables,%
arduino:mbed:envie_m7,-752,-0.1,-16,-0.0,-816,-0.1,-24,-0.0,-816,-0.1,-16,-0.0,0,0.0,0,0.0
arduino:mbed_giga:giga,-824,-0.04,-8,-0.0,,,,,,,,,0,0.0,0,0.0
arduino:mbed_nicla:nicla_vision,-824,-0.04,-8,-0.0,,,,,,,,,0,0.0,0,0.0
arduino:mbed_opta:opta,-816,-0.04,-32,-0.01,-760,-0.04,-40,-0.01,,,,,0,0.0,0,0.0