Support code auto-completion for brokerProperties in editor

[gaohoward]

The brokerProperties need a lot manual work to configure by users. The user needs to remember the configuration syntax as well as various property names in order to get the config right.
In the editor it would be great to add auto completion feature to aid users.

[lavocatt]

We were discussing this topic with @gtully the other day. My understanding of it was that, we don't want to publicize the use of broker properties too much, and we don't want to make them "easy to use" because the main vision is to move away from the current model that is "deploying brokers for some needs" to "onboarding applications on running brokers".

I think having a conversation on that topic would be very good during one of the next meetings with the operator folks.