Purpose

Sub task of ZKP-41. To eventually deprecate use of serde on non primitive data types.

Changes

Guard non primitive serde::Serialize, serde::Deserialize behind a flag. List of data types can be found here

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.