e2e: Add logfile

[nirs]

The e2e logs are not detailed enough for debugging. We want to add detailed DEBUG level message. This will be too much info for the console so we need a log file. A log file is good idea anyway since it is hard to insepct the logs in the console, specially after running commands with lot of output.

Tasks:

• Add logfile in the current directory, using the name of the e2e executable (e.g. ramen-e2e.log)
• Create the log file by default
• Use DEBUG level to log file, INFO for console
• Upload the log as build artifacts in e2e job
• Remove caller (file:lineno) from console logs

Example similar zap logging configuration:
https://github.com/nirs/kubectl-gather/blob/baccfc4a37aa9edbecfe466563a15bc23e48cc13/cmd/root.go#L133

Initial work: #1607
Quick hack: #1723