BUG: cosmosim query url doesn't exists

The module both requires authentication, and doesn't have tests, so this was under the radar for who knows how long:

```
Not found

The requested URL was not found on this server.
```

Unless someone steps up in the very near future, I would suggest removing the module just as we did with the other modules that stopped functioning and had no immediate support. This removal can be temporary in a way that the module can be resurrected and fixed up from history.

Things to do to avoid removal:
- fix the queries (swapping out the URL to https://www.cosmosim.org/query/ should likely work)
- as I see, guest access is possible, so at bare minimum we should be able to do that from here, and use it for testing.
- add tests

cc @keflavich and @agroener

Locate the cosmosim module and first reproduce its query failure against the current service URL. Check whether guest access works, then update the queries, add coverage for the supported access path, and verify the tests exercise successful requests; if the service cannot be supported, review the removal approach described in the issue.

Written by the indexing model from the issue text.