[SSHD-1330] Using common keep-alive global request handler in client as well as server

[lgoldstein]

No description provided.

[lgoldstein]

@tomaswolf Please review and merge if you are satisfied - thx.

[tomaswolf]

Moving the KeepAliveHandler to a different package will break any code that currently references it using the old package. Not sure how to deal with this.

[lgoldstein]

Valid point, but IMO

• The change is minor - package shift - so easily fixed whenever the referencing code is re-compiled with the new version
• I doubt there is much existing code referencing it directly
• Not the first time we shifted some classes + not something we are doing often

In view of this I think we can safely merge this piece of code.