Update data sent to mappers to be compliant with mappers v2

[snip]

Since mappers migrated to v2, 2 things needs to be updated: (see https://docs.helium.com/use-the-network/coverage-mapping/mappers-api/#ingest-uplink)

• Injest URL needs to be updated to production one
• hdop & sats seems not to be anymore used. Instead we need to transmit accuracy field

This requeires change in:

• README.md to update the self mapping function
• disk91's backend to use new format (behind https://dev.disk91.com/fieldtester/helium/v3)
• and maybe the radio protocol (as i'm not sure we already get the accuracy information)

Mappers v2 announcement: https://discord.com/channels/404106811252408320/730418759298318346/859580354792390666 https://twitter.com/helium/status/1410021512673910788

[snip]

accuracy can maybe be calculated thanks to a fomula likes the following:

accuracy=(HDOP*2+5)/10
if(accuracy>63) accuracy=63

[snip]

Remak regarding filtering of data according to GPS accuracy: https://discord.com/channels/404106811252408320/730801390431240228/860161652917534770

So maybe all data should be sent whatever the GPS locatation accuracy we get as it will be in the future filtered at UI side.

[snip]

Fixed by https://github.com/disk91/WioLoRaWANFieldTester/commit/8d8a7d8b9f25a2f9fd52ef57768591d105323f7e. Backend also updated.