Consider a new name for `TimeZone.of`

[dkhalanskyjb]

It doesn't seem idiomatic. of is just visual noise that doesn't tell anything about what argument to expect. It's unclear right now what it should be called instead: it's a bit too effectful for a constructor function (as it queries the timezone database), it's far from a pure computation.

[TarunVishwakarma1]

TimeZone.get or TimeZone.fromId can be good new names

Confirmation - does the file changes required in kotlinx-datetime/core/common/src/TimeZone.kt are there any more files?