Make columns types an empty list for empty tabular data

[bernt-matthias]

• show number of columns [Feature Request] Tabular dataset improvement: show lines and columns #13258
  • could also be rows x cols (I.e. drop the words lines and columns) for compacter display
  • empty files currently get 0 lines 1 colums?
    • @dannon mentioned that this is because there are tables with enormous numbers of columns (but I don't see this breaking since there is only a max no of lines limit, or?)
      • there is a 1MB limit in the line number estimation function, but the number of columns is taken from the properties filled by set_meta which reads MAX_LINES .. question is if we can assume that set_meta runs before set_peek?
    • guess we should fix this and cover this with a test for Tabular.set_meta .. should this be an inline unit test or another way
    • not entirely sure if fix is 100% correct, since files with a single empty column are now also 0 column files. this is because the tabular datatype assumes empty lines as comments which are not used to determine empty columns
• shorter display of estimated number of lines line number approximation of tabular data #6506
  • also thought if K, M, G... suffixes might be nicer

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[jdavcs]

Assigning the 22.09 milestone. Please remove if this is premature.

[jdavcs]

Thank you, @bernt-matthias! Sorry for delaying with this review!

[github-actions]

This PR was merged without a "kind/" label, please correct.