feat: UI table formatting

[mattrunyon]

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

Features

• Multiple formatting rules allowed on one table
• Last 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 if_ 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
• E2e tests
• Testing/setting good error messages if if_ is bad. Other potential error points we might want to add
• 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

Follow-ups

• ui.table formatting databar mode #981
• ui.table format default values #983
• ui.table format values from a column #984
• Support wildcard and regex column patterns for table formatting #961

Example Code

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

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

[mofojed]

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?)

@mattrunyon Perhaps this could tie into the work for #549 (setting Undefined instead of None to get the default, for example). @wusteven815 will be working on that ticket soon.

[dsmmcken]

Can we add a sections for each formatter? Helps both SEO and shows a functional example of how to accomplish each task

#### Formatting table background colors

#### Formatting table decimals

#### Formatting table dates
...

[mattrunyon]

I think it would make more sense to do Formatting Colors and Formatting Values unless you want each of those sections to be 1 or 2 sentences. That feels like overkill to me to show someone what "changing the background color to red" does or "changing text alignment to left".

I think formatting colors would explain what kind of color values you can use and what values can take colors.

Formatting values would link out to appropriate docs about value format strings (I think they're Java formatting strings, but need to verify)

[margaretkennedy]

Formatting colors and Formatting values sound reasonable in terms of avoiding super short sections; however, if a user is likely to search "Formatting table dates" and similar, it might be worth it.

[mattrunyon]

I ended up adding Formatting Colors as an h3 to describe you can (and should) use theme colors. Then text/background color as h4.

For values I added an h3 for numeric and datetime

[mofojed]

Looks good, a couple of minor fixes/notes. Would be nice if we could pass in a column name for the column or format value as well (with those taking precedent; e.g. if you have a column named RED, that value would take precedent over the colour RED).

I also tested with a large number of columns to make sure weren't getting caught with stuff out of the viewport, and it seems to work correctly:

from deephaven import empty_table, ui
colors=["RED", "GREEN", "BLUE"]
cols = [f"C_{i}=i" for i in range(1, 100)]
t = empty_table(1000).update([*cols, "x=i", "c=`` + colors[i%3]", "RED=`` + colors[(i + 1)%3]"])
ut = ui.table(t, formatting=[ui.TableFormat(where="C_3%2==0", color="RED")])

[margaretkennedy]

Formatting colors and Formatting values sound reasonable in terms of avoiding super short sections; however, if a user is likely to search "Formatting table dates" and similar, it might be worth it.

[mofojed]

Looks good to me. Curious what @dsmmcken thinks of using if_ and format_

[dsmmcken]

Curious what @dsmmcken thinks of using if_ and format_

I kinda hate it. I assume that's because those are both keywords in python? Did I miss a discussion somewhere?

[dsmmcken]

Approving docs, not a fan of if_ or format_ but I defer to you guys. Pending accepting @margaretkennedy changes.

I wouldn't hate cond=