Add capability to support steam boilers (1st gen district systems)

[vtnate]

Any background context you want to provide?

Level 1 (reading from a sys-param file) only for a steam example.

What does this PR accomplish?

• Adds new parameters to the schema
• Adds templates to use the new values
• Adds tests for steam systems

How should this be manually tested?

CI is sufficient

What are the relevant tickets?

Screenshots (if appropriate)