[SG-10] Refactor Cipher data model

[Hinton]

Type of change

• [ ] Bug fix
• [x] New feature development
• [ ] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
• [ ] Build/deploy pipeline (DevOps)
• [ ] Other

Objective

Draft refactor of the cipher data model. Replaces the data with a serialized instance of EncObject which is controlled by the clients.

Code changes

• file.ext: Description of what was changed and why

Before you submit

• [ ] I have checked for formatting errors (dotnet tool run dotnet-format --check) (required)
• [ ] If making database changes - I have also updated Entity Framework queries and/or migrations
• [ ] I have added unit tests where it makes sense to do so (encouraged but not required)
• [ ] This change requires a documentation update (notify the documentation team)
• [ ] This change has particular deployment requirements (notify the DevOps team) …itional-item-types