cmake: Improve the usage of PARENT_SCOPE

Merge branch 'cmake_remove_libs' into 'master'

cmake: Remove the intermediate static libs

See merge request !7

cmake: do not use intermediate libraries at all (not even OBJECTS)

cmake: Remove the intermediate static libs

Should compile faster (and also take less space on disk)

Free the result pointer provided by udns

Fix a memory leak that would occur on every DNS request, when using udns

Revert "Don’t send the unavailable presence to all resources, in the virtual channel"

This reverts commit 38ff50f5d2ca356f659429ff57546bd2364a0fef.

Don’t send the unavailable presence to all resources, in the virtual channel

Document the ad-hoc configure forms

Reduce the scope of a variable

Pass the shared_ptr by reference, to avoid useless copies

Little refactor in timed_events

Also makes the coverage code deterministic

Small resolver refactor

Makes the codecoverage deterministic (it does not depend on the order of
v4/v6 resolution)

Replace : with _ in the codecov flag

Use CI_BUILD_NAME as the codecov tag

ci: Use the build:7 artifacts for test:without_udns

ci: Run a e2e test without udns (and upload to codecov)

e2e: Make the tests work without udns too

Do not pass the build artifacts to packaging:deb job

Improve the make coverage_* commands

ci: refactor, comments, use the artifacts from a stage to the next