feat(rust, python): deprecate 'use_earliest' argument in favour of 'ambiguous', which can take expressions

[MarcoGorelli]

closes #10090 (note: if it's OK, I'll work on adding the new options suggested in that issue in separate PRs, this one's already quite large)

Before: when-then-otherwise gymnastics

df = pl.DataFrame(
    {
        "ts": [datetime(2020, 10, 25, 1), datetime(2020, 10, 25, 1)],
        "use_earliest": [True, False],
    }
)
df.with_columns(
    ts_london=pl.when(pl.col("use_earliest"))
    .then(pl.col("ts").dt.replace_time_zone("Europe/London", use_earliest=True))
    .otherwise(
        pl.col("ts").dt.replace_time_zone("Europe/London", use_earliest=False)
    )
)

After: just pass an expression

df = pl.DataFrame(
    {
        "ts": [datetime(2020, 10, 25, 1), datetime(2020, 10, 25, 1)],
        "ambiguous": ["earliest", "latest"],
    }
)
df.with_columns(
    ts_london=pl.col("ts").dt.replace_time_zone(
        "Europe/London", ambiguous=pl.col("ambiguous")
    )
)

Similarly for .dt.truncate, .dt.to_datetime, and pl.datetime

[ritchie46]

Looks good to me! 👍