docs: Getting started demo + sandbox

[Jayclifford345]

I have added a getting-started demo based on the ride-share app. This takes users through the basics of using Pyroscope to identify a bottleneck within the application code provided. This tutorial also provides a interactive sandbox for the user to try out this demo: https://killercoda.com/grafana-dev-testing/course/pyroscope/ride-share-tutorial

Unfortunately, there is an unusual bug within the Profile Explorer app (when using the sandbox) for which I am seeing help. For now, I have tagged this within the sandbox and once fixed will remove the notice. The rest of the sandbox which uses the Pyroscope UI works great! There is also a grafana play link so they can try this there

{{<docs/ignore>}}
{{< admonition type="tip" >}}
Unfortunately, due to a bug within the Sandbox environment, the profile explorer app is currently unavailable. We are working on a fix and will update this tutorial once resolved. If you would like to try out the profile explorer app, you can run the example locally on your machine. Or you can try out this example in [Grafana Play](https://play.grafana.org/a/grafana-pyroscope-app/profiles-explorer?searchText=&panelType=time-series&layout=grid&hideNoData=off&explorationType=labels&var-serviceName=pyroscope-rideshare-python&var-profileMetricId=process_cpu:cpu:nanoseconds:cpu:nanoseconds&var-dataSource=grafanacloud-profiles&var-groupBy=all&var-filters=)
{{< /admonition >}}
{{</docs/ignore>}}

I belive for now the rest of the demo is good enough to get out there. Many thanks in advance for the review!

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[knylander-grafana]

I'll be looking at this today and tomorrow. Thank you!