[#69995588] Move Vcloud::QueryRunner under Vcloud::Core 

Move Vcloud::QueryRunner under Vcloud::Core to comply with breaking
changes introduced in vcloud-core version 0.1.0.

Also bumps the dependency on vcloud-core in the Gemspec so that we use
version 0.1.0.

Note that I haven't bumped the version number for vcloud-net_launcher in this PR as there are further namespace changes we'd like to make (#70162466) before bumping the minor version.

Depends on https://github.com/alphagov/vcloud-core/pull/30.

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Also fixes the version number of the most recent release in `CHANGELOG.md`.