Set up basic card listing, particularly tagged

+ Simplify stash calls to stash:embed shortcuts
+ Add layout_listing_description and layout_listing blocks
+ Set up proper stash:nocache areas for banner and css/js areas.
+ Add parse_stage=“both” to templates so that nocache areas will be
parsed, while everything else gets saved to the db
+ Set up listing view model
+ Clean up old /blog/tag/ paths from blog index template

Related to issue #30