Cleanup cucumber tables (and automate the process)

@kevgo 

Add a script to cleanup and lint cucumber tables.

No longer need to properly indent cucumber tables by hand. Just update the table with the proper data and run  `bin/clean_cucumber` which will indent and align the tables properly. Added a linter as well so you committing an ill-formatted table will cause the build to break (it will tell you to run `bin/clean_cucumber`).
Can you use the more descriptive long form of command-line options here? I think we need to distinguish two cases here:
* normal code analysis (linting) mode: exit with error code in case there are issues. Don't fix them. This should be used here, and on CI.
* auto-fix mode: fixes issues that it finds.

Command-line options could be `--lint` and `--fix` or something like that.