Add CSV importer

[Astn]

We should add a new command for importing CSV files.

We would need them specify which column is the ID column, along with other columns that should be references.

Something like this might get us started.

load csv 
(
  IMPORT "a" as apple, "c" as "cherry","d" as dog, "e" as eee, "f"  
  FROM "URI" 
  HEADERS ("a","b","c","d","e","f","g","h","i")
  KEY "a" 
  REFERENCE ("c","f")
)

The idea being that you specify which columns you want to include in the import using either the list of columns or maybe a "*" to include all.

You then specify the URI where that data is loaded from.

Optionally if your csv does not include headers you can specify those after the from statement.

KEY to specify which column is the Key REFERENCE to specify which columns are foreign keys

Sub Tasks

• [ ] Grammar enhancement
• [ ] Parser Listener
• [ ] CSV Importer