OAuth2 supported HttpClient in core module

# Background:
We have an OAuth2 in action #186 in the authorjapps/zerocode-hello-world#7 repo. But it can be made as part of the core module. Since the OAuth2 implementation was generic enough to support most of the providers it will benefit many people.

# AC1:
Follow this as reference or suggestion only(but check the latest IETF doc for standard impl):
https://github.com/authorjapps/zerocode/pull/676#pullrequestreview-2274484012
+ Internet Engineering Task Force (IETF) standard

# AC2:
+ Log (WARN level) the access_token details or log the response
+ Log (WARN level) client_id and client_secret by masking it (e.g. for "secret123", log `"s***3"`or `"***"` to avoid extra logic)

and

+ Log (INFO level) client_id and client_secret as it is(without any masking)

Start by locating the core module's HttpClient entry point and review issue #186, the referenced pull-request review, and the latest IETF OAuth2 guidance. Done means generic OAuth2 provider support is incorporated and the specified WARN- and INFO-level credential and access-token logging behavior is addressed.

Written by the indexing model from the issue text.