Resolve "Update Gitlab to work with Istio sidecar injection"

Add istio sidecar injection. To make istio injection work, annotations are conditionally added to certain jobs (init containers) to disable injection. The annotations are only added if istio is enabled.
All changes are backwards compatible with BigBang. No breaking changes because istio injection is already disabled by default.
Note that some annotations can be added by chart values (migrations and shared-secrets) and are therefore set in the BigBang template. Some init jobs (minio-create-buckets and upgrades) cannot be configured with chart values. Those are implemented by modifying the gitlab sub-charts.
Note: the gitlab issue #60 will be closed by the BigBang MR. Istio injection for Gitlab will not actually happen until the BigBang MR gets merged.

Also, bump resources for gitaly
closes #106 (closed)