feat: HTTP Trigger

[loicmathieu]

Fixes kestra-io/kestra#2299

Flow to test the new trigger:

id: http-trigger
namespace: dev

triggers:
  - id: http
    type: io.kestra.plugin.fs.http.Trigger
    uri: https://api.chucknorris.io/jokes/random
    responseCondition: "{{ response.statusCode == 200 }}"

tasks:
  - id: hello
    type: io.kestra.core.tasks.log.Log
    message: Kestra team wishes you a great day! 👋

[anna-geller]

why response instead of trigger.statusCode? just thinking whether this is not confusing where the response variable is coming from as it's usually trigger.XYZ

[anna-geller]

forget my previous comment, this makes sense, the trigger variables can be used in tasks - sorry, my misinterpretation

works!

id: http-trigger
namespace: dev


tasks:
  - id: hello
    type: io.kestra.core.tasks.log.Log
    message: "{{trigger.body}}"

triggers:
  - id: http
    type: io.kestra.plugin.fs.http.Trigger
    uri: https://api.chucknorris.io/jokes/random
    responseCondition: "{{ response.statusCode == 200 }}"
    interval: PT30S

[loicmathieu]

The trigger variables are normally to use in the triggered Flow tasks as you noticed, here we evaluate the trigger.
So I decided to call it response as it's a variable only usable when evaluating the trigger property responseCondition.

However, I can rename it.

I can also totally remove the responseCondition property and only rely on the standard conditions property where you can use a condition of type VariableCondition. But I found it more logical to define the evaluation condition like this. The responseCondition will be evaluated prior to any standard trigger conditions.

[Skraye]

Small indent detail, however LGTM