[AL-3329] Document Annotation Type for Export

[jtsodapop]

This PR is designed to:

• create a new annotation type class for documents which will test against if an export annotation contains page and unit
• Add this to extra field when it exists, else it passes back None

Rough example output:

name='boxy' 
feature_schema_id='cl6xnuwt95lqq07330tbb3mfd' 
extra={'instanceURI': 'https://api.labelbox.com/masks/feature/cl6xnzjpq0dmx07yo0qh40z0n?token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiJja2NjOWZtbXc0aGNkMDczOHFpeWM2YW54Iiwib3JnYW5pemF0aW9uSWQiOiJja2N6NmJ1YnVkeWZpMDg1NW8xZHQxZzlzIiwiaWF0IjoxNjYwNzYxNDUwLCJleHAiOjE2NjMzNTM0NTB9.X4-j6zee8o685PUrL9C6oC2m6TayKuJQHhN8iLgG8kI', 
'color': '#1CE6FF', 
'feature_id': 'cl6xnzjpq0dmx07yo0qh40z0n', 
'value': 'boxy', 
'page': 3, 
'unit': 'POINTS'} 
value=Rectangle(extra={}, start=Point(extra={}, x=83.34, y=298.12), end=Point(extra={}, x=83.72, y=501.95000000000005)) classifications=[] 

[kkim-labelbox]

Some questions around this:

1. What's the difference between labelbox_v1 representations of annotations versus stuff inside serialization/ndjson ?
2. Do we need a new rectangle object type specific to document? I don't see this pattern used for other data types, e.g. Video or Images

[jtsodapop]

Some questions around this:

1. What's the difference between labelbox_v1 representations of annotations versus stuff inside serialization/ndjson ?
2. Do we need a new rectangle object type specific to document? I don't see this pattern used for other data types, e.g. Video or Images

not sure if you receive an update when I make a reply, so re-tagging @kkim-labelbox !

1. labelbox_v1 representation is just the transformations between the labelbox export and the annotations themselves. the ndjson converter is for transformations between the annotations and a labelbox import format (which will be done in a separate PR)
2. there will be nothing different between the existing bounding box annotation for other data types such as image, and this one. the only difference is the page and unit keys from the export.

i set this up this way since i thought it would make more sense to just re-use the LBV1Rectangle code as there are no required additional changes, but if it would make more sense to paste the same code in for this new class, i am open to it

[kkim-labelbox]

LGTM!

[jtsodapop]

Will update changelog once import side has also been complete!