Use dcaccount scheme with a domain name instead of URL

[link2xt]

Once the core is updated with chatmail/core#7360
this line

deltachat-android/src/main/java/org/thoughtcrime/securesms/InstantOnboardingActivity.java

Line 127 in bc372d5

providerQrData = DCACCOUNT + ":https://" + providerHost + "/new";

should be changed to use DCACCOUNT + providerHost as the default QR code when the core is updated.

This will make it use no-HTTPS onboarding.

Desktop PR: deltachat/deltachat-desktop#5618
iOS issue: deltachat/deltachat-ios#2855