LaTeX template: Fix booktabs vertical spacing

To adjust the vertical space between rows inside tables, the `booktabs` package
provides `\belowrulesep` and `\aboverulesep`. The default values are:

    \belowrulesep=.65ex
    \aboverulesep=.4ex

To adjust the vertical space between the bottom rule and the caption, use
`\belowbottomsep`. The default value is 0pt. For example:

    \belowbottomsep=\belowrulesep