refactor(api): refactor the implementation of windowing

[chloeh13q]

Description of changes

Some design considerations:

• Removed the original implementation of windowing to avoid confusion.
• I thought about creating a window class to hold all the relevant windowing info like window type, window size, window slide, etc. The API would be slightly cleaner that way but I worry that it would be confused with the existing ibis.window().
• Tumble and hop are the most basic types of windows that we should support across the board. Session windows and cumulate windows are not supported in every backend and the API is slightly different.

The new API:

>>> import ibis
>>> from ibis import _
>>> t = ibis.table(
...     ibis.schema(
...         {
...             "createTime": "timestamp(3)",
...             "orderId": "int64",
...             "payAmount": "float64",
...             "payPlatform": "int32",
...             "provinceId": "int32",
...         }
...     ),
...     name="payment_msg",
... )
>>> expr = (
...         t.window_by(time_col="createTime")
...         .tumble(size=ibis.interval(seconds=30))
...         .agg(by=["provinceId"], avgPayAmount=_.payAmount.mean())
...     )
>>> expr
r0 := UnboundTable: payment_msg
  createTime  timestamp(3)
  orderId     int64
  payAmount   float64
  payPlatform int32
  provinceId  int32

WindowAggregate[r0]
  window_type:
    tumble
  time_col:
    r0.createTime
  groups:
    provinceId: r0.provinceId
  metrics:
    avgPayAmount: Mean(r0.payAmount)
  window_size:
    30 s
  schema:
    window_start timestamp
    window_end   timestamp
    provinceId   int32
    avgPayAmount float64

Issues closed

#8847