AST-1477 Fix pages job by excluding xtensor from coverage
Exclude coverage of _deps, so the pages job works again on the SKA mirror.
- Those files are already gone in the pages job.
- IDG shouldn't report coverage of xtensor and xtl, which are in _deps.
Also simplify how IDG uses xtensor libraries, using link_libraries
.
https://gitlab.com/ska-telescope/sdp/ska-sdp-func-idg/-/merge_requests/4 shows that this MR indeed fixes the pages job.
Edited by Maik Nijhuis