LocalDocument should support appending values to fields

[laserval]

Currently, appending values to a field involves:

• Checking if their is such a field
• Checking the type of the field
• Typecasting the value of the field
• Creating a list if the field is not already a list
• Adding the new value of the field

Supporting an append of some sort would make it easier to write stages.

[remen]

👍