Add `renameAll {}` DSL

[Jolanrensen]

Renaming multiple columns at once is a hassle,
especially when you want to use column accessors or the compiler plugin.

The options currently are:

df.rename { all() }.into {
    when (it.name) {
        "arter" -> "species"
        "ø" -> "island"
        "næblængde_mm" -> "bill_length_mm"
        "næbdybde_mm" -> "bill_depth_mm"
        "luffelængde_mm" -> "flipper_length_mm"
        "kropsmasse_g" -> "body_mass_g"
        "køn" -> "sex"
        "måledato" -> "measurement_date"
        else -> error("for ${it.name}")
    }
}

This is unsafe and might break, plus the compiler plugin cannot interpret it.

df.rename(
    "arter" to "species",
    "ø" to "island",
    "næblængde_mm" to "bill_length_mm",
    "næbdybde_mm" to "bill_depth_mm",
    "luffelængde_mm" to "flipper_length_mm",
    "kropsmasse_g" to "body_mass_g",
    "køn" to "sex",
    "måledato" to "measurement_date",
)

While the compiler plugin can interpret this code, it can still contain typos, so I'd count it as unsafe too.

df.rename { all() }.into(
    "species",
    "island",
    "bill_length_mm",
    "bill_depth_mm",
    "flipper_length_mm",
    "body_mass_g",
    "sex",
    "measurement_date"
)

Order dependent, which is seldom a good thing

df
    .rename { arter }.into("species")
    .rename { ø }.into("island")
    .rename { næblængde_mm }.into("bill_length_mm")
    .rename { næbdybde_mm }.into("bill_depth_mm")
    .rename { luffelængde_mm }.into("flipper_length_mm")
    .rename { kropsmasse_g }.into("body_mass_g")
    .rename { køn }.into("sex")
    .rename { måledato }.into("measurement_date")

The safest solution, but a hassle to type out every time, and not very readable

df.select {
    cols(
        arter into "species",
        ø into "island",
        næblængde_mm into "bill_length_m",
        næbdybde_mm into "bill_depth_mm",
        luffelængde_mm into "flipper_lenth_mm",
        kropsmasse_g into "body_mass_g",
        køn into "sex",
        måledato into "measurement_date",
    )
}

Funnily enough, the most readable solution doesn't even use the rename operation ;P that should be a good indication we need improvement.

I'd suggest:

df.renameAll {
    arter into "species"
    ø into "island"
    næblængde_mm into "bill_length_m"
    næbdybde_mm into "bill_depth_mm"
    luffelængde_mm into "flipper_lenth_mm"
    kropsmasse_g into "body_mass_g"
    køn into "sex"
    måledato into "measurement_date"
}

We cannot reuse rename {} because it doesn't return a DataFrame.
We would need to carefully shadow into from the ColumnsSelectionDsl, but otherwise, we should be fine.