feat(helm): adds a flag for tokengen rbac components so that they can be disabled optionally

[drew0ps]

What this PR does / why we need it:

This PR adds the option to disable the RBAC manifests from the tokengen component. This is needed for enterprise kubernetes offerings where developers/service owners are not allowed to deploy rbac related manifests, only specific workload related ones. In such cases, deploying the RBAC manifests are typically done separately after approval or by an infrastructure team.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• 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

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