Token creation functions

### Is your feature request related to a problem?

_No response_

### Describe the solution you'd like

Having functions to create tokens (fungible & non fungible) will help the dApps devs. This way they don't need to deal with the json content at all.

Plus, if we change the schema for some reason, we could simply update the SDK and dApps devs would not have to change their implementation.

### Additional context

_No response_

### Epic

_No response_

The issue names no files, tests, or entry points. Start by reviewing the libgo SDK's existing token-related APIs and JSON handling, then clarify the fungible and non-fungible token schemas and expected function interfaces. Done means both token types can be created without dApps constructing JSON directly, with coverage for the agreed behavior.

Written by the indexing model from the issue text.