Sylvain Henry authored Jan 12, 2023 and Marge Bot committed Feb 17, 2023

`libiserv` serves no purpose. As it depends on `ghci` and doesn't have
more dependencies than the `ghci` package, its code could live in the
`ghci` package too.

This commit also moves most of the code from the `iserv` program into
the `ghci` package as well so that it can be reused. This is especially
useful for the implementation of TH for the JS backend (#22261, !9779).