This function needs to be removed because of the following problem:
When linking from one entry to another, and then removing the link in
the first entry with ::set_internal_links(vec![]), we end up with a
dangling link in the second entry, because the ::set_internal_links()
function does not take care of removing the links in the "other"
entries.
Actually, it is not even able to do so, because it would need to
`Store::get()` those entries, but it does not have access to the store.
Adding a `store` parameter to the function would be possible, but only
increase its complexity unnecessarily. This is why I opt for removing
this function (which is btw not used once in the whole imag codebase).
Signed-off-by: Matthias Beyer <mail@beyermatthias.de>