While many of the most fundamental limitations of `pulumi logs` are still dependent on moving this code out of pulumi/pulumi and into pulumi-aws and other resource providers (https://github.com/pulumi/pulumi/issues/608), this PR implements a few more tactical fixes which improve some common scenarios.
Fixes#2665.
Fixes#1926.
Fixes#3947.
We have to reverse engineer the name from the soruce LogGroup information since that is all we got at runtime, but luckily that is sufficient given current name generation approach.
This kind of code is *very* sensitive to any changes to automatic name generation - but that is likely inevitable at this layer.