allow passing retry arguments down to gapic layer

[daniel-sanche]

The high-level, hand-written logger.log methods are the recommended way of interacting with the library, but they lose some of the power of the low-level, gapic methods. For example, gapic methods allow you to pass in custom "retry" logic. We should allow users to pass those arguments to the high-level methods, and pass them on down the stack