Consider changing convert { }.to { } operation

[koperagen]

df.convert { }.asColumn { } restricts name change
df.convert { }.to { } is the same as df.replace { }.with { } - and even recommended as such in the documentation
We could either restrict name change in df.convert { }.to { }, keep it as is, or remove df.convert { }.to { }
related to #1143

[Jolanrensen]

I vote for removing df.convert { }.to { } because it's confusingly named the same as df.convert { }.to<Int>(). It's not clear from the name when to choose to/with whereas asColumn/with is easier