Update loki values and update loki to 6.3.4-bb.0

Package Merge Request

Package Changes

Package	Update	Change
loki	major	2.9.6 -> 3.0.0
docker.io/grafana/loki-canary	major	2.9.6 -> 3.0.0
gluon	patch	0.4.8 -> 0.5.0
registry1.dso.mil/ironbank/opensource/kubernetes/kubectl	minor	v1.28.8 -> v1.29.3
grafana-agent-operator (source)	patch	0.3.19 -> 0.3.21

As a result of changes to the loki chart, it is also necessary to make some tweaks to the loki template in BB umbrella.

Package MR

big-bang/product/packages/loki!166 (merged)

For Issue

Closes big-bang/product/packages/loki#102 (closed)

Upgrade Notices

Loki 3.0 is a major version increase and comes with several breaking changes.

Here is the shortlist of things we think most people may encounter:

• Structured metadata is enabled by default and requires tsdb and v13 schema or Loki won't start. Refer to Structured Metadata, Open Telemetry, Schemas and Indexes.
• The shared_store config is removed. Refer to Removed shared_store and shared_store_key_prefix from shipper configuration.
• Loki now enforces a max line size of 256KB by default (you can disable this or increase this but this is how Grafana Labs runs Loki). Refer to Changes to default configure values.
• Loki now enforces a max label limit of 15 labels per series, down from 30. Extra labels inflate the size of the index and reduce performance, you should almost never need more than 15 labels. Refer to Changes to default configure values.
• Loki will automatically attempt to populate a service_name label on ingestion. Refer to service_name label.
• There are many metric name changes. Refer to Distributor metric changes, Embedded cache metric changes, and Metrics namespace.
• loki.index_gateway.mode must remain set to simple. Setting it to ring will result in pod crashes due to a bug in loki 3.0.0. Reference: https://github.com/grafana/loki/issues/12270
• Distributed deployment mode is now available using the Loki chart. However not yet supported/available using the umbrella Big Bang chart. This will be implemented and tested in a future release.