Support schema and data change events in Data Explorer protocol

[wesm]

UI side of https://github.com/posit-dev/positron-python/pull/389.

There is a parameter indicating whether the DE tab should reset the state of UI components like sorting or filter, so we will need to address that in a follow up PR

[wesm]

you can use code like this to test

import numpy as np
import pandas as pd

df = pd.DataFrame({'a': [1, 2, 3, 4]})

df = pd.DataFrame(
    {
        "a": [1, 2, 3, 4],
        "b": [True, None, False, True],
        "c": ["Ohio", "Florida", None, "California"],
    }
)

df = pd.DataFrame(
    {
        "a": [-1.0, 0.0, 3.0, 4.0],
        "b": [1, 2, 3, 4],
        "c": [True, None, False, True],
        "d": ["Ohio", "Florida", None, "California"],
    }
)

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[petetronic]

Using your branch I was able to see updates (edits, additions, deletions) to the DataFrame reflected live in the DataExplorer.