Use single dependency to render tables

[jsoriano]

There are some elastic-package subcommands that render tables in their output. For this rendering we use two different dependencies, that generate slightly different outputs.

• tablewriter is used in cmd package, we use its colorized output.
• go-pretty is used in test and benchmark reports, we don't use colors so far there.

For consistency we should use the same kind of tables, and use the same package for rendering them.

As part of this task we should decide what package to use.

Check also consistency of output used (stderr vs stdout): #2590 (comment)

See discussion in #2590 (comment)