Added message formatting for prom alerts

      slack_configs:

      - channel: '#sandbox_alerts'

        send_resolved: true

        icon_url: https://avatars3.githubusercontent.com/u/3380462

        title: |-

          [{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}

          {{- if gt (len .CommonLabels) (len .GroupLabels) -}}

            {{" "}}(

            {{- with .CommonLabels.Remove .GroupLabels.Names }}

              {{- range $index, $label := .SortedPairs -}}

                {{ if $index }}, {{ end }}

                {{- $label.Name }}="{{ $label.Value -}}"

              {{- end }}

            {{- end -}}

            )

          {{- end }}

        text: >-

          {{ range .Alerts -}}

          *Alert:* {{ .Annotations.title }}{{ if .Labels.severity }} - `{{ .Labels.severity }}`{{ end }}

          *Description:* {{ .Annotations.description }}

          *Details:*

            {{ range .Labels.SortedPairs }}  *{{ .Name }}:* `{{ .Value }}`

            {{ end }}

          {{ end }}