Update tempo dashboards

[mmkay]

Summary

Adjust the current tempo dashboard with panels that make sense in a non-distributed setup from upstream tempo mixins: https://github.com/grafana/tempo/tree/main/operations/tempo-mixin-compiled/dashboards

I've also added an "at a glance" overview at the top. The PR is obviously impossible to go through as it's a bunch of dashboards json so some screenshots of added sections follow:

Testing Instructions

Pack the charm from the branch and use the following bundle:

bundle: kubernetes
applications:
  alertmanager:
    charm: alertmanager-k8s
    channel: edge
    revision: 103
    series: focal
    resources:
      alertmanager-image: 87
    scale: 1
    constraints: arch=amd64
    storage:
      data: kubernetes,1,1024M
    trust: true
  catalogue:
    charm: catalogue-k8s
    channel: edge
    revision: 33
    series: focal
    resources:
      catalogue-image: 32
    scale: 1
    options:
      description: "Canonical Observability Stack Lite, or COS Lite, is a light-weight,
        highly-integrated, \nJuju-based observability suite running on Kubernetes.\n"
      tagline: Model-driven Observability Stack deployed with a single command.
      title: Canonical Observability Stack
    constraints: arch=amd64
    trust: true
  grafana:
    charm: grafana-k8s
    channel: edge
    revision: 106
    series: focal
    resources:
      grafana-image: 67
      litestream-image: 43
    scale: 1
    constraints: arch=amd64
    storage:
      database: kubernetes,1,1024M
    trust: true
  loki:
    charm: loki-k8s
    channel: edge
    revision: 122
    series: focal
    resources:
      loki-image: 91
    scale: 1
    constraints: arch=amd64
    storage:
      active-index-directory: kubernetes,1,1024M
      loki-chunks: kubernetes,1,1024M
    trust: true
  prometheus:
    charm: prometheus-k8s
    channel: edge
    revision: 171
    series: focal
    resources:
      prometheus-image: 140
    scale: 1
    constraints: arch=amd64
    storage:
      database: kubernetes,1,1024M
    trust: true
  tempo:
    charm: local:tempo-k8s-19
    scale: 1
    constraints: arch=amd64
    storage:
      data: kubernetes,1,1024M
  traefik:
    charm: traefik-k8s
    channel: edge
    revision: 171
    series: focal
    resources:
      traefik-image: 158
    scale: 1
    constraints: arch=amd64
    storage:
      configurations: kubernetes,1,1024M
    trust: true
relations:
- - traefik:ingress-per-unit
  - prometheus:ingress
- - traefik:ingress-per-unit
  - loki:ingress
- - traefik:traefik-route
  - grafana:ingress
- - traefik:ingress
  - alertmanager:ingress
- - prometheus:alertmanager
  - alertmanager:alerting
- - grafana:grafana-source
  - prometheus:grafana-source
- - grafana:grafana-source
  - loki:grafana-source
- - grafana:grafana-source
  - alertmanager:grafana-source
- - loki:alertmanager
  - alertmanager:alerting
- - prometheus:metrics-endpoint
  - traefik:metrics-endpoint
- - prometheus:metrics-endpoint
  - alertmanager:self-metrics-endpoint
- - prometheus:metrics-endpoint
  - loki:metrics-endpoint
- - prometheus:metrics-endpoint
  - grafana:metrics-endpoint
- - grafana:grafana-dashboard
  - loki:grafana-dashboard
- - grafana:grafana-dashboard
  - prometheus:grafana-dashboard
- - grafana:grafana-dashboard
  - alertmanager:grafana-dashboard
- - catalogue:ingress
  - traefik:ingress
- - catalogue:catalogue
  - grafana:catalogue
- - catalogue:catalogue
  - prometheus:catalogue
- - catalogue:catalogue
  - alertmanager:catalogue
- - catalogue:catalogue
  - loki:catalogue
- - loki:logging
  - traefik:logging
- - traefik:grafana-dashboard
  - grafana:grafana-dashboard
- - loki:logging
  - tempo:logging
- - tempo:tracing
  - alertmanager:tracing
- - tempo:grafana-dashboard
  - grafana:grafana-dashboard
- - tempo:grafana-source
  - grafana:grafana-source
- - tempo:tracing
  - grafana:tracing
- - tempo:tracing
  - loki:tracing
- - tempo:metrics-endpoint
  - prometheus:metrics-endpoint
- - tempo:tracing
  - prometheus:tracing
- - tempo:tracing
  - traefik:tracing
- - traefik:ingress
  - tempo:ingress