Replace requests to POST /action/index with POST /action/query where possible

[isc-bsaviano]

Copied from #110 (comment)

For the specific case of hovering over a class name, I could replace the POST /action/index call with a POST /action/query call that only returns the exact info that I need (just the description). Testing on a local IRIS using Postman, here's what the benefit looks like for %Persistent:

POST /action/index (current behavior)

["%Library.Persistent.cls"]

Returns 76.25KB of data in ~14ms

POST /action/query (proposed behavior)

{
    "query": "SELECT Description FROM %Dictionary.CompiledClass WHERE Name = ?",
    "parameters": ["%Library.Persistent"]
}

Returns 684B of data in ~8ms

While this isn't a meaningful change when you're connected to a local IRIS or one on a fast network, transferring ~75KB fewer would likely be noticeable on a slower network like yours.