Remove hoogle search from vscode-haskell

[fendor]

This extension provides rudimentary support for querying hoogle from within vscode.

The feature is barely maintained, and we most likely don't even know if it is still working, but it contributes a considerable amount of direct dependencies to this extension.

Let's remove it, and if anyone requires this feature, they shall be pointed to https://github.com/haskell-spotlight/haskell-spotlight which does the same thing, but much better.

[fendor]

PR #896 removed the hoogle feature from this repo. Keeping this open for now, to communicate this change.