Add Hive and Impala to landing page navbar links

[szlta]

Hive and Impala are missing from the integration's list on the top of the landing page. Fixing this.

[szlta]

cc: @pvary @samredai

[pvary]

@samredai: It this ok?

[szlta]

This was required so that Project and ASF don't fold their down-shevron icon.

[samredai]

We're actually going to remove the list of engines from the top navbar in favor of a "Quickstart" item that takes you to a collection of various quickstarts. So external links to engine support pages for Iceberg will only exist in the leftnav of the docs page. This is from the proposal that was presented back in the April community sync that everyone agreed on.

I actually already have PR #75 open that removes them and adds the first quickstart (Spark). You can see a video here of how the quickstarts will apear once there are more added. Please feel free to add a Hive and/or Impala quickstart and let me know if there's anything I can do to help!