Add Deprecation to SmartSim Docs

[MattToast]

Description

SmartSim is deprecated and we need to make that clear to users who stumble upon our docs. We can also point them toward RHAPSODY.

Justification

It would be nice to point users away from SmartSim and toward successor projects.

Implementation Strategy

We can do this by adding a deprecation banner to:

• the SmartSim docs
• the SmartSim README