Add SmartModule support w/ WASI workflow in docs

[tjtelan]

In This week in Fluvio #24 we walk through compiling Fluvio w/ WASI support.

This is a valuable workflow for a (very) technical user developing SmartModules, and it belongs somewhere in the docs so we don't lose it.

The current structure doesn't provide an obvious place for this to live, so this may need to wait for reorganization to occur first.

[ajhunyady]

I think we'll need reorganize our documentation in the following areas:

• Data Streams
• Intelligent Streams
• Connectors
• Pipelines

That should give us to add "WASM" related content in "Intelligent Streams"
I suggest we open a PR on the content hierarchy to start tackling these issues.