Add charm tracing

[mmkay]

Issue

COS config charm didn't have charm tracing support

Solution

Add charm tracing and tracing libraries and integrate COS config charm with tracing.

Testing Instructions

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
  cos-config:
    charm: local:cos-configuration-k8s-0
    series: focal
    scale: 1
    options:
      git_branch: main
      git_repo: https://github.com/canonical/cos-configuration-k8s-operator
      grafana_dashboards_path: tests/samples/grafana_dashboards/
    constraints: arch=amd64
    storage:
      content-from-git: kubernetes,1,1024M
  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: 124
    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-k8s:
    charm: tempo-k8s
    channel: edge
    revision: 30
    resources:
      tempo-image: 15
    scale: 1
    constraints: arch=amd64
    storage:
      data: kubernetes,1,1024M
  traefik:
    charm: traefik-k8s
    channel: edge
    revision: 174
    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
- - cos-config:tracing
  - tempo-k8s:tracing
- - tempo-k8s:grafana-source
  - grafana:grafana-source
- - cos-config:grafana-dashboards
  - grafana:grafana-dashboard