Feature: services can be customized with http timeout values

[kggilmer]

Several AWS services have specific timeout values they specify for HTTP reads. The Kotlin SDK should allow for the specification of a service read timeout.

Open questions:

1. does this timeout need to be adjusted at the operation level as well?
2. what's the intersection of this and CRT-provided retry logic?
3. should this be overridable by customers?

[kggilmer]

Related: /bin/view/Public/AwsDrTools/SDKs/TimeoutGuidance/