MDL-44364 theme_more: More settings to style the theme
MDL-44364 theme_bootstrapbase: Improve variable usage

The rules or selectors removed appeared either not to be used any more
or were enforcing a rule that was not adequate and should not be
replaced by a variable. Basically, the focus was to simplify our
usage of the colours and variables to use LESS more efficiently.
MDL-44364 theme_bootstrapbase: Clean up calendar variables