Migrate K8s quickstart manifests to tanka v2

[hjet]

PR Description

This PR migrates the generation of K8s manifests in production/kubernetes to v2 of the Tanka jsonnet library.

Summary of changes to manifests:

• (all) Change default Agent http port to 80 from misc other ports (8080, 12345, etc)
• agent-bare.yaml
  • Becomes a StatefulSet (prev Deployment)
  • Add headless Service for StatefulSet
• agent-loki.yaml
  • machine-id (journal) vol disabled by default
• agent-traces.yaml
  • make namespace templatable
  • change svc port names (no functional change)
  • remove config generation from jsonnet (TODO in a future PR: add this to tanka/v2 jsonnet library)

Which issue(s) this PR fixes

Fixes #451

Notes to the Reviewer

Still need to test these on clusters and update docs but submitting for preliminary review
Tested manifests on a DOKS cluster

PR Checklist

• CHANGELOG updated
• (Agent) Documentation added

[hjet]

cc @rgeyer re: impact on k8s integration onboarding instructions (change default from Deployment to StatefulSet)
cc @mapno re: impact on traces quickstart changes (the config remains the same and lives in cloud docs here)

[hjet]

I've integrated all the review comments. Note that we should hold off on merging this until the onboarding plugin instructions and docs changes are ready to go (although this is a bit of a chicken-egg situation).

[rgeyer]

LGTM

[rfratto]

merge block to prevent accidental merges; feel free to dismiss once it's ready to go

[rfratto]

@hjet following up on this, do you know if this is safe to merge now?

[hjet]

(Mostly) safe to merge per https://github.com/grafana/cloud-docs/pull/142 however it would be prudent to also restart all hosted Grafana instances to pick up the latest version of the plugin to eliminate all possible stale references to main

[hjet]

Going to work through the merge conflict in a bit

[hjet]

@rfratto just rebased, should be good to go.

i decided to use defaults for the HTTP port/server everywhere, will create issues in the cloud-docs repo to track the required config/configmap changes. those docs are versioned now (to v0.23) so will be unaffected by this, and will require more significant updates anyways upon next release (to capture change from deployment -> statefulset, etc..)

[hjet]

See https://github.com/grafana/cloud-docs/issues/143 for Cloud docs issue

[rfratto]

LGTM % one small nit