[WIP] Several styling fixes, robust styling approach, re-organization…

… of styles

Relatedly
- Removes 'aside' element (in some layouts it doesn't correspond to its meaning)
- Removes 'titleLines' prop since this is (and needs to be) controlled by layout
- Removes /deep/ selectors in favor of using 'headingStyles' prop (the
implementation dependet on nested selectors with /deep/ in the
middle, however it only seemed to work by chance when missing scss language
config. For <style scoped lang="scss"> it caused the page compilation
break.

docs/pages/kcard.vue

@@ -405,4 +405,4 @@
     font-weight: bold;
   }
 
-</style>
+</style>