XWIKI-10545: Use the snapshots extension repository by default for snapshot builds
- Added the snapshotModules profile that is to be run in order to include the snapshots repository.
- Enterprise tests use a system variable to disable the snapshots repository since it will be present (from previous CI builds) but we don't want it enabled.
Merge pull request #60 from xwiki/XWIKI-10545-v2

XWIKI-10545: Use the snapshots extension repository by default for snapshot builds