Bug#991025: merkaartor build depends on both libqt5webkit5-dev and qtwebengine5-dev but uses neither

[Adrian Bunk]

Source: merkaartor
Version: 0.19.0~rc1+ds-1
Severity: serious

1. the build dependency on libqt5webkit5-dev looks stale
2. the build dependency on qtwebengine5-dev should be
   [amd64 arm64 armhf i386 mipsel] since these are the
   architectures where the package exists
3. on these 5 architectures, configuring with USEWEBENGINE=1
   is required to actually use it

Severity set to RC since 2. would currently prevent migration
to bookworm.