Determine non-overlapping UX for Confluent Local Connection and Direct Connection (to local resources)

[rohitsanj]

With #396 and some of the other related PRs that adds functionality to start/stop local Kafka/SR containers from the extension itself, we should think about ways to sufficiently differentiate/disambiguate this experience from that of being able to establish Direct Connections to a locally running Kafka/SR setup.

Here are some rough ideas (open to debate):

• What if we introduced the concept of a "Local Playground" (what is today just "Local") that the user may spin up with a single button click? This would accurately signal the ephemeralness as well as the purpose of the locally running environment: to play around with setting up multiple networked Kafka brokers, produce/consume messages to topics with multiple partitions, create/view schemas, etc, and to be able to tear it all down and start over again if needed.
• I don't think we should be exposing the Confluent Local Kafka REST URL (http://localhost:8082) like we do today (See screenshot). The user shouldn't care that there's a Kafka REST server running. If anything, surfacing the existence of a Kafka REST server is distracting and adds cognitive load. (Would appreciate some more experienced perspectives here)

• We may eventually choose to implement the "Local Playground" using the Direct Connection type and remove all references to the "Local" connection type, however, this must be done in a way that is opaque to the user since they wouldn't really care what type of connection the playground belongs to. The "Local Playground" then becomes a Direct Connection that's fully managed by VS Code rather than by the user and perhaps we have a flag that indicates this.