feat(steps): implement DiscretizeKBins transform

[jitingxu1]

Added KBinsDiscretizer
It supports:

• Uniform strategy: Divides data into bins of equal width based on the minimum and maximum values of each column.
• Quantile strategy: Divides data into bins with an equal number of samples in each bin.

Examples:

import ibis
import ibisml as ml
from ibisml.core import Metadata
ibis.options.interactive = True

p = ibis.examples.penguins.fetch()
step = ml.KBinsDiscretizer(
    ml.numeric(),
    strategy="quantile",
    overwrite=True,
    )
step.fit_table(p, Metadata())
step.transform_table(p)

Outputs:

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━┩
│ string  │ string    │ int8           │ int8          │ int8              │ int8        │ string │ int8 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼──────┤
│ Adelie  │ Torgersen │              1 │             3 │                 0 │           1 │ male   │    0 │
│ Adelie  │ Torgersen │              1 │             2 │                 0 │           1 │ female │    0 │
│ Adelie  │ Torgersen │              1 │             3 │                 2 │           0 │ female │    0 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │    0 │
│ Adelie  │ Torgersen │              0 │             4 │                 1 │           0 │ female │    0 │
│ Adelie  │ Torgersen │              1 │             4 │                 1 │           1 │ male   │    0 │
│ Adelie  │ Torgersen │              1 │             2 │                 0 │           1 │ female │    0 │
│ Adelie  │ Torgersen │              1 │             4 │                 2 │           3 │ male   │    0 │
│ Adelie  │ Torgersen │              0 │             3 │                 1 │           0 │ NULL   │    0 │
│ Adelie  │ Torgersen │              1 │             4 │                 1 │           2 │ NULL   │    0 │
│ …       │ …         │              … │             … │                 … │           … │ …      │    … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴──────

Resolves #44

[deepyaman]

Suggested change

	else:
	warnings.warn(
	f"No column selected for discretization - {self.inputs!r}.",
	stacklevel=2,
	)

I don't know that this is necessary, and I don't see any other step with it. The existing behavior is to just skip doing anything if there's no columns selected.

I'd be open to considering a warning across the board, but I think it should be done in a separate issue then.

[jitingxu1]

I will create an separate issue for this.

Changes addressed, and not re-reviewing right now to unblock testing