Adds three integration jobs covering supported Redis topologies:
- integration:redis (single-node)
- integration:redis:cluster
- integration:redis:sentinel

Topology setup is handled by small bash scripts under
v2/redis/testdata/ci/.

I would have prefered to re-use out docker-compose files, which can be
used to run these tests locally. However, setting the Cluster and
Sentinal instance via scripts allows us to avoid messing with
`network_mode: host` / DIND networking complexities.

Use `set -euo pipefail` per Duo review feedback

Uses -skip 'Cluster|Sentinel' to exclude topology-specific tests from the
single-node job, preventing future tests starting with C or S from being
silently excluded.

ci: wire v2/redis integration tests into CI pipeline

See merge request !502

Merged-by: Matias Alvarez <malvarez@gitlab.com>
Approved-by: Matias Alvarez <malvarez@gitlab.com>
Reviewed-by: GitLab Duo <gitlab-duo@gitlab.com>
Reviewed-by: Matias Alvarez <malvarez@gitlab.com>
Co-authored-by: Luke Hollinda <lhollinda@gitlab.com>