operator: Add serviceaccount per lokistack resource

[JoaoBraveCoding]

What this PR does / why we need it:
The lokistack pods used for run using the default serviceaccount on the install namespace except for the lokista-ck-gateway and ruler pods that requested serviceaccounts and corresponding token secrets for external activities (e.g. SubjectAccessReviews, Alertmanager authentication)

The present PR adds a single shared serviceaccount per LokiStack resource to be used by the rest of the components. This enables using the projected account token for authentication against cloud providers (e.g., managed identity services like STS and WIF).
Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:
This is a preparation action for:

• operator: adds AWS sts support #11481

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• CHANGELOG.md updated
  • If the change is worth mentioning in the release notes, add add-to-release-notes label
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[github-actions]

Trivy scan found the following vulnerabilities:

• HIGH, Target: docker.io/grafana/loki:main-a760cdf (alpine 3.18.4), Type: alpine openssl: Incorrect cipher key and IV length processing in libcrypto3 v3.1.3-r0. Fixed in v3.1.4-r0
• HIGH, Target: docker.io/grafana/loki:main-a760cdf (alpine 3.18.4), Type: alpine openssl: Incorrect cipher key and IV length processing in libssl3 v3.1.3-r0. Fixed in v3.1.4-r0
  \nTo see more details on these vulnerabilities, and how/where to fix them, please run docker build -t grafana/loki:main-a760cdf -f cmd/loki/Dockerfile .
  trivy i grafana/loki:main-a760cdf on your branch. If these were not introduced by your PR, please considering fixing them in via a subsequent PR. Thanks!