Refactoring serialization and deserialization types

[aaraney]

Meta-issue for tracking progress porting dmod libraries to pydantic.

• Refactor dmod.core Refactor dmod.core serialization and deserialization types #239 (resubmitted Refactor dmod.core serialization and deserialization types #256)
• Refactor dmod.communication Refactor dmod.communication serialization and deserialization types  #253
• Refactor dmod.scheduler Refactor dmod.scheduler serialization and deserialization types  #270
• Refactor dmod.modeldata Refactor dmod.modeldata serialization and deserialization types #257
• Merge updates to master into feature branch
• Pydantic Refactoring #279

[aaraney]

#253 and #257 are ready for review. dmod.scheduler refactor is in progress.

[aaraney]

#270 is done and ready for review.

[robertbartel]

With the completion of #331, we can call this done.