refactor(sdk): conversion methods

[shumkov]

Issue being fixed or feature implemented

Different entities has different naming for to/from methods (toValue, toObject, ...)

What was done?

• Rename methods.
• Make sure fromObject / toObject are returning plain JS Object

How Has This Been Tested?

With existing tests

Breaking Changes

Many methods are renamed

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have added "!" to the title and described breaking changes in the corresponding section if my code contains any
• I have made corresponding changes to the documentation if needed

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone

Summary by CodeRabbit

Release Notes

• New Features

  • Added JSON and object-based constructors (fromJSON, fromObject) for enhanced serialization support across assets, identities, and data contracts.

• API Changes

  • Standardized method naming for consistency: base58() → toBase58() and base64() → toBase64() across all classes.
  • Improved parameter type handling for network-related methods.