feat: add fields to BigPanda alert

[rhajek]

This PR improves BigPanda alerting:

• by default BP Alert contains all field values and tags
• BigPanda primary and secondary property is configurable in tick script or in topic handler

alert
  .bigPanda()
  .appKey('fc39458f98e91eb0310258c3b725d643')
  .primaryProperty('device')
  .secondaryProperty('sensor_name')
  .topic('bigpanda-topic')

or in topic hadler

id: bigpanda-cpu-alert
topic: bigpanda-topic
kind: bigpanda
options:
  app-key: '8f5795cada387b9f310f41fc369c88e4'
  primary-property: 'host'
  secondary-property: 'check'
  url: 'http://localhost:8080/data/v2/alerts'

Required for all non-trivial PRs

• Rebased/mergable
• Tests pass
• CHANGELOG.md updated
• Sign CLA (if not already signed)

Required only if applicable

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• TICKscript Spec updated