cad/PrusaSlicer: unbreak and few slight fixes
This commit unbreaks build by hackish change to restore V1 API usage of libboost
and migrating to soup-3.0 (usage of v4.1 flavor of webkit2gtk)
PR: 287255
Reported by: mirror176@hotmail.com
Approved by: teodorsigaev@gmail.com (maintainer)
Sponsored by: Postgres Professional