Add ability to use custom `RequestAdapter` with `URLSessionClient`

[subdan]

AlamofireClient can be created by passing baseURL or RequestInterceptor:

public init(
    requestInterceptor: RequestInterceptor,
    ...

public convenience init(
    baseURL: URL,
    ...

But the URLSessionClient can be created by passing baseURL only.

public init(
    baseURL: URL,
    ...

Users who use URLSessionClient unable to use custom request interceptor (RequestAdapter).

Add new init with RequestAdapter parameter.

public init(
    requestAdapter: RequestAdapter,
    ...