Support params_file / composed target for passing secrets (e.g. accessKey) to HTTP probes

[Racarii]

We have an HTTP probe to an external ITSM endpoint:
https://abc.com/sd/services/rest/check-status?accessKey=<UUID>
accessKey is an API key, and we don’t want to store it in git inside configs.
Problem:
To call this ITSM API, we must hardcode accessKey in the target URL in git
Feature request:
Add something like params_file for the HTTP prober (similar to body_file) to load extra query params/headers from a file/secret.
Or allow composing the final target URL from multiple params (e.g. base_url + extra query params), so that secrets can be passed separately and not stored directly in git.