Document and test DataColumnArithmetics.kt

[Jolanrensen]

DataFrame supports many DataColumn arithmetics like /, +, *, etc. but they are undocumented (both in KDocs and on the website).

This should be done and made sure it's discoverable.

Also, ! is missing for boolean columns.

[Jolanrensen]

AI likes to think it's possible to write colA + colB: pairwise operations. At the moment we only support colA + value, but it may be worth considering the other notation as well.

There are some downsides though; there would need to be quite a few overloads for this, combining all number types etc.

[koperagen]

Please refer to this discussion when implementing #1617