[Developer Workflow] Making PRs easier to review

[foxish]

As discussed in today's meeting.
One issue with reviewing PRs is the volume of changes that are typical (500+ lines of changes), in which major parts tend to be boilerplate or fabric8 client code.
In order to speed up reviews, mechanisms suggested were:

1. Discuss the top-2 most complex PRs in the SIG itself, spending ~5 minutes on each, with the author running us through the important parts
2. Have more descriptive PR descriptions [pointing to specific files/"business logic"] to help cut through the noise.
3. Secondary meetings where interested folks discuss and talk about specific parties (for PRs that may need more collaboration)

Thoughts?
cc @apache-spark-on-k8s/contributors