Make Ronja plan SKIP and LIMIT together with ORDER BY
Add Cost and Cardinality for SORT, SKIP and LIMIT
Add new pipes

o Add LimitPipe, SkipPipe and a new SortPipe
o Rename the old SortPipe to LegacySortPipe
Let projection be done before sorting

When sorting, a row needs to be compared with other
rows quickly and multiple times. To facilitate this,
force projection to happen, so sorting doesn't have
to execute an expression for every comparison.