feat: add webhooks for major events: clone creation, etc. (#514)

⚠ this MR is closed – all worked moved to the 4.0 branch: !763 (merged)

Description

Add webhooks for major events

• Extend DLE config to support webhooks (clone_create, clone_reset, clone_delete)
• Support webhook configuration reloading
• Make requests and report status and response to logs
• Filter webhook secrets in logs

Related issue

#514

Examples

Configuration

webhooks:
  hooks:
    - url: "http://127.0.0.1:2345/healthz"
      secret: "secret-token"
      trigger:
          - clone_create
          - clone_reset

Basic Payload

{
  event_type string
  entity_id   string
}

Clone Payload

{
  event_type string
  entity_id  string
  host       string
  port       uint
  username   string
  dbname     string
}

Logs output

2023/05/25 18:40:58 webhooks.go:107: [DEBUG]  Trigger event: {{clone_create chnqnem1q2ss73bt6i5g} localhost 6000 john postgres}
2023/05/25 18:40:58 webhooks.go:116: [INFO]   Webhook request:  http://127.0.0.1:2345/healthz
2023/05/25 18:40:58 webhooks.go:142: [DEBUG]  Webhook Payload:  {"event_type":"clone_create","entity_id":"chnqnem1q2ss73bt6i5g","host":"localhost","port":6000,"username":"john","dbname":"postgres"}
2023/05/25 18:40:58 logging.go:16: [INFO]   ->  POST /healthz
2023/05/25 18:40:58 webhooks.go:125: [DEBUG]  Webhook status code:  200
2023/05/25 18:40:58 webhooks.go:133: [DEBUG]  Webhook response:  {"version":"v3.4.0-rc.5-34-g1e790c9f-20230525-1840","edition":"community","instanceID":"cdhk35u1q2ss73eqa0ng"}

...

2023/05/25 18:41:39 webhooks.go:107: [DEBUG]  Trigger event: {{clone_reset chnqnem1q2ss73bt6i5g} localhost 6000 john postgres}
2023/05/25 18:41:39 webhooks.go:116: [INFO]   Webhook request:  http://127.0.0.1:2345/healthz
2023/05/25 18:41:39 webhooks.go:142: [DEBUG]  Webhook Payload:  {"event_type":"clone_reset","entity_id":"chnqnem1q2ss73bt6i5g","host":"localhost","port":6000,"username":"john","dbname":"postgres"}
2023/05/25 18:41:39 logging.go:16: [INFO]   ->  POST /healthz
2023/05/25 18:41:39 webhooks.go:125: [DEBUG]  Webhook status code:  200
2023/05/25 18:41:39 webhooks.go:133: [DEBUG]  Webhook response:  {"version":"v3.4.0-rc.5-34-g1e790c9f-20230525-1840","edition":"community","instanceID":"cdhk35u1q2ss73eqa0ng"}

Checklist

• MR description has been reviewed
• MR changes are functionally tested
• MR does NOT have API/CLI changes OR there are API/CLI changes and they have been reviewed & DOCS ARE ADJUSTED (reference doc, etc)
• MR does NOT have UI changes OR there are UI changes and they have been reviewed & UX IS REVIEWED

Closes #514