feat(python,rust): updated default table format from "UTF8_FULL" to "UTF8_FULL_CONDENSED"

[alexander-beedie]

Closes #5942

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Format updates

• Changes default UTF8 table format from UTF8_FULL to UTF8_FULL_CONDENSED.
• Changes default ASCII table format from ASCII_FULL to ASCII_FULL_CONDENSED (requiring comfy-table 6.1.4).
• Updates all docstrings to match the new format (in both Python & Rust).

# shape: (3, 3)                    shape: (3, 3) 
# ┌────────────┬─────┬──────┐      ┌────────────┬─────┬──────┐
# │ dt         ┆ x   ┆ y    │      │ dt         ┆ x   ┆ y    │
# │ ---        ┆ --- ┆ ---  │      │ ---        ┆ --- ┆ ---  │
# │ date       ┆ f64 ┆ f64  │      │ date       ┆ f64 ┆ f64  │
# ╞════════════╪═════╪══════╡      ╞════════════╪═════╪══════╡
# │ 2022-12-26 ┆ 3.5 ┆ 10.0 │      │ 2022-12-26 ┆ 3.5 ┆ 10.0 │
# ├╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌┤      │ 2022-12-27 ┆ 4.0 ┆ 2.5  │
# │ 2022-12-27 ┆ 4.0 ┆ 2.5  │  >>  │ 2022-12-28 ┆ 1.0 ┆ 1.5  │
# ├╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌┤      │ 2022-12-29 ┆ 6.0 ┆ 6.0  │
# │ 2022-12-28 ┆ 1.0 ┆ 1.5  │      │ 2022-12-30 ┆ 0.0 ┆ 11.5 │
# ├╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌┤      │ 2022-12-31 ┆ 2.0 ┆ 0.0  │
# │ 2022-12-29 ┆ 6.0 ┆ 6.0  │      └────────────┴─────┴──────┘
# ├╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌┤
# │ 2022-12-30 ┆ 0.0 ┆ 11.5 │
# ├╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌┤      (improves usage of vertical space)
# │ 2022-12-31 ┆ 2.0 ┆ 0.0  │
# └────────────┴─────┴──────┘

Also

• Registers a doctest tearDown function to prevent any pl.Config changes inside docstrings from leaking scope.
• Adds a note inside the sign docstring to explicitly state the expected return values: -1 (+ve), 0 (zero), 1 (-ve).

[ritchie46]

Big thanks to the man who gets superpowers from a cup of tea. ^^

[alexander-beedie]

Lol.... never leave home without one! ☕
Happy New Year :)