Add RestClient implementations

[sjohnr]

To Do:

• Add unit tests
• Add integration tests
• Add reference documentation

This PR adds implementations of OAuth2AccessTokenResponseClient that use RestClient as the underlying HTTP client. These implementations offer behavior and configuration similar to the WebClient-based implementations, which provides consistency for issues such as gh-11298 and gh-14811. See theme issue gh-15299 for more context.

Closes gh-15298

[sjohnr]

Closed via 2cead9b