[DOC]: Create how-to use Property Graph for analytic workflows

[acostadon]

Create a How-To on Property Graph:

• Starting PG
• Adding data
• filtering and subgraph extraction

[acostadon]

• [ ] Define Property Graph and the problems it solves
• [ ] Define a workflow that makes use of the PG including analytics.
• [ ] Create a PG and add edge/vertex data
• [ ] Run an analytic what will generate data used in the follow-up
• [ ] Load the analytic data back into the PG
• [ ] Run a follow-up algorithm on an extraction from the PG
• [ ] Link to API and supporting Documents from PG