Add initial version of example workspace

[planger]

An example workspace should help users to conventiently try out CDT.cloud blueprint. On the long run it should allow to try all components of CDT.cloud, however, let's start with something simpler and incrementally extend over time.

We may want to start out with the example workspace of clangd-context. The steps for instantiating this example project should at least be described on the welcome page, or a dedicated command that creates such a project in the current workspace.

[sdirix]

TraceCompass example traces can be found in the Trace Visualization Labs

[planger]

Fyi, I started creating a command that creates the example project of clangd-context.