[Feature Request]: Support "import hierarchy" in language server

[jabraham17]

Today, we already make use of the call hierarchy feature of LSP to show the chain of calls that are used for a given function. Modules can also have similar chains, via use/import. An interesting feature to explore is if we can show an "import hierarchy" using the same LSP feature.

This would for a given import show which modules that brings in, and then which modules those bring in, and so on. This could also be used to show all the places a given module is used.

This is likely a bigger effort, as we would need to plumb more dyno scoping features in chapel-py and need to figure out how to "hack" the call hierarchy to work with imports