Cleaner source generation: refactor as template
[core] Add factories for single column row lists,
to create a list with initial values:

```java
import acolyte.RowLists;
import acolyte.RowList1;

// Creates a row list with 3 rows "A", "B" and "C"
RowList1<String> list = RowLists.stringList("A", "B", "C");
```