chore: deprecate templatebody from http check

[adityathebe]

resolves: #1584

[adityathebe]

To avoid excessive escaping on the templates we might want to simply turn off templating on some fields. Example: we could do it via annotations

apiVersion: canaries.flanksource.com/v1
kind: Canary
metadata:
  name: http-fail
  labels:
    "Expected-Fail": "true"
  annotations:
    canary.template.disabled: 'http.body, http.url' # <-----
spec:
  interval: 30
  http:
    - endpoint: https://httpbin.demo.aws.flanksource.com/status/500
      name: http fail response code check
      responseCodes: [200]
    - endpoint: https://httpbin.demo.aws.flanksource.com/status/200
      name: http fail test expr check
      display:
        expr: string(code) + " should be 500"
      test:
        expr: code == 500

Should this be sufficient

canary.template.disabled: 'http.body, http.url'

or do we want to individually disable templating on the http check. Eg

canary.template.disabled: 'http[0].body, http[1].url'