Include JMX Monitoring stacks on Gitpod configuration

[jeqo]

Description

What behavior does this PR change, and why?

While enabling gitpod on jmx-monitoring-stacks repo (https://github.com/confluentinc/jmx-monitoring-stacks/pull/54), it made sense to extend cp-demo instead of copy/paste'ing most of the gitpod configuration in another project.

This PR adds a new variable MONITORING_STACK to choose which stack to start, if any, when starting cp-demo on gitpod.

Author Validation

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Reviewer Tasks

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[gitpod-io[bot]]

[vdesabou]

Am I the only one getting for https://gitpod.io/#https://github.com/confluentinc/cp-demo/pull/401 ?

[jeqo]

@vdesabou it works for me: https://gray-bee-8m5ifxwq.ws-us17.gitpod.io/

[chuck-confluent]

I'm working on some other gitpod prebuild optimizations in https://github.com/confluentinc/cp-demo/pull/419 that would need to go through before adding this. Hold tight, and thank you for contributing this!

[chuck-confluent]

Sorry for the delay on this. I've since discovered that CP demo is pushing the resource limitations of gitpod quite a bit, so i don't think it's feasible to run more components. I'll have to close this PR, unfortunately.