Add support for Sensirion SHT3X

[MKBastler]

Adds support for Sensirion SHT-3X sensors. Tested with SHT-31 and a Heltec-V3 sensor:

This PR should address #565 and #1849

[MKBastler]

Please note that this my first PR to a major open-source project. If there's anything that keeps this from getting merged, please drop a message so I can rectify the issue.

[petrkr]

Vote +1 for this as I have also board with this temp sensor... It is tested working code, should not break anything.

[Tomas-Kuchta-FPV]

Hi, I also had this idea of making my first pr and implementing SHT3x. 😅

#3095

[Tomas-Kuchta-FPV]

It looks we went almost the same route. They've changed a few things so this needs updating.

Also what about INA266 as it has the same adress.

[MKBastler]

Hello everyone,

sorry for the inactivity. @Tomas-Kuchta-FPV you´re right, there has been a bigger overhaul for the SensorManager since this has been opened, so this PR will definitely not work for the modern versions. I´ll make myself familiar and update to the new scheme hopefully in next few weeks. As for the INA266, that´s a type of conflict that´s probably unavoidable with this many sensors being supported. While the SHT3X does support a secondary adress with 0x45, I do not yet see a good mechanism to deal with an adress conflict in the SensorManager. This is probably something that needs a dedicated PR.
Have a nice day,
MK