Rehydrate a pager from a URL

Another method we could add to #2205 is to allow construction of a `Pager` from a link like the initial page link or `next_link` in a page eg.,

```rust
let mut pager = Pager::::from_link("...")?;
```

Some languages have this while others do not.

Start with issue #2205 and the Pager API described here, including the initial page link and next_link examples. Define done as allowing a Pager to be constructed from a URL such as those links, while preserving the stated Result-style usage.

Written by the indexing model from the issue text.