`core` improve `FeignUtil` `BaseBuilder` to allow the client to choose the `Feign` logger as well as the `Feign` `LogLevel`

improve `FeignUtil` `BaseBuilder` to allow the client to choose
* its `Feign` logger
* as well as the `Feign` `LogLevel`

see https://github.com/adobe/aio-lib-java/pull/145#discussion_r1094850264

It looks like the Feign Logger API is under refactoring see
* https://github.com/OpenFeign/feign#short-term---what-were-working-on-now-
* https://github.com/OpenFeign/feign/issues?q=is%3Aissue+is%3Aopen+logger+label%3Afeign-12
* https://github.com/OpenFeign/feign/issues/1143

a few Feign logging related articles:
* https://cloud.spring.io/spring-cloud-openfeign/reference/html/#feign-logging
* https://medium.com/@piszu/feign-client-is-not-so-simple-as-we-want-case-study-920e4901e27b

从 FeignUtil 的 BaseBuilder 开始，查看已链接 pull request 中的讨论，然后阅读所引用的 Feign logger API 材料，以了解当前的 logger 和 LogLevel 接口。完成的标准是：客户端可以通过 builder 同时选择 Feign logger 和 Feign LogLevel，而不会受到正在进行的 Feign API 重构的阻碍。

由索引模型根据 Issue 内容生成。