skaffold should provide an easy way to fetch debug level logs from the previous run

Skaffold should record debug-level logs as well as regular skaffold output to some file such as `~/.skaffold/last.log`. This file name should be configurable. This file could be attached to bug reports to aid in diagnosis.
This file can also include:
* Skaffold version number
* Skaffold command-line
* Environment variables (sorted)
* Version numbers and locations of other tools such as docker, kubectl, kustomize, helm
* User's operating system and architecture, and RAM.