feat: UI table formatting

[mattrunyon]

Fixes #596. Adds UI table formatting based on the spec.

Features

• Multiple formatting rules allowed on one table
• First matching rule for a formatting type is applied
• Single dataclass (ui.TableFormat) which encompasses the potential formatting options
• The cols parameter applies formatting to specific columns. The where parameter provides further filtering for rows
• DH theme color keywords supported in addition to hex and CSS keyword colors
• If a background color is specified with no text color, a contrasting black/white text color is applied

Missing

• Docs
• Unit tests (should pull out some of the model code around formatting to test it easier)
• E2e tests
• Testing/setting good error messages if where is bad. Other potential error points we might want to add
• Databars through formatting option (follow-up PR?)
• Default as a keyword for all values. Could be useful if you want to apply a background color and not a font color that may have no where clause later in the list. (follow-up PR?)
• Regex/wildcard column name matching (follow-up PR)
• Number formatting rules can be applied to date columns since they're actually longs. I think this is fine as just something to note instead of trying to determine if a formatting option is date/number specific

Example Code

from deephaven import ui
import deephaven.plot.express as dx

t = ui.table(
    dx.data.stocks(),
    formatting=[
        ui.TableFormat(background_color="positive", where="Sym=`DOG`", color='negative'),
        ui.TableFormat(
            cols=["Sym", "Exchange"], background_color="negative", where="Sym=`CAT`"
        ),
        ui.TableFormat(cols=["Sym", "Exchange"], alignment="center"),
        ui.TableFormat(cols="Size", color="notice", where="Size > 100"),
        ui.TableFormat(cols="Size", color="info", where="Size < 10"),
        ui.TableFormat(cols="Timestamp", value="E, dd MMM yyyy HH:mm:ss z"),
        ui.TableFormat(value="0.00%"),
    ],
)