[Feature Request] Introduce secret_key Parameter for Authentication

[justinh-rahb]

Is your feature request related to a problem? Please describe.
The current reliance on Bearer-Token for API authentication can be restrictive for environments where managing headers is less practical. Some users may find it easier to pass authentication details as part of the query or request body, especially in certain automated or legacy systems.

Describe the solution you'd like
Implement a secret_key parameter that can be used as an alternative authentication method. This parameter would allow users to authenticate their API requests by appending secret_key=[USER_SECRET_KEY] to the query parameters, offering flexibility for different integration scenarios.

References
https://github.com/apilayer/screenshotlayer-API/blob/master/docs/specifications.md