[Docs] Explain how the type system and data passing works in Flyte Fundamentals

[cosmicBboy]

Description

Currently the Flyte Fundamentals don't cover the flyte type system of how data passing works between tasks and workflows. The purpose of this issue is to create a new docs page (probably under "Tasks, Workflows and LaunchPlans") that provides an overview of:

• the flyte type system: how it works, when to use it, how the type engine works, limitations
• data passing: provide a clear mental model of how data is handled in a workflow execution

Are you sure this issue hasn't been raised already?

• Yes

Have you read the Code of Conduct?

• Yes