* #8839 update all col-xs-* in Orchard.Layouts module to just col-* to fix columns. col-xs-* was removed in Bootstrap 4. display:flex was also added to Row.less to counteract the display:block on all the divs between .row and the .col-*
* Remove unnecessary file update. Didn't mean to include this, it is part of the Bootstrap 3 source which is not used anymore.
* OrchardCMS#8839 fixes for the layout editor from the previous work. If multiple elements were in a column, they were displaying horizontally instead of vertically. In order to fix this and manage situations where there are nested rows, the CSS specification had to be high.
* Rebuild client-side assets
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Co-authored-by: Benedek Farkas <benedek.farkas@lombiq.com>
