Attribute calculation

[jhoetter]

Is your feature request related to a problem? Please describe.
Similar to pandas, I want to be able to create new attributes given some logic to apply.

Describe the solution you'd like
This could look very similar to labeling functions, e.g. as follows:

def cat_attributes(record):
    return str(record["attr1"]) + str(record["attr2"])

to concatenate two textual attributes.

To avoid data clutter, this should also allow users to a) distinguish between original attributes in the data and b) delete attributes

Describe alternatives you've considered
Changing the data before you upload it - very static and not dev friendly

Additional context
I already implemented a proof-of-concept before our OS release :)

[jhoetter]

related to issue #14

[jhoetter]

Mockups

We could integrate a modifiers section in the project settings page, where users see what attribute calculations they have (similar to a pandas DataFrame):

We could "reuse" what we have for the labeling functions IDE:

[FelixKirsch]

implemented in release v1.3.0