docs: add initial token info

[thephez]

Adds documentation for token functionality including:

• Token Overview: Explanation of Dash Platform's token model, features, and use cases.
• Token Actions: Minting, transferring, burning, freezing/thawing, emergency actions, and configuration updates.
• Token Configuration: Parameters for supply limits, access control, distribution rules, and history retention.
• Rules & Permissions: Admin and control level rules for managing token updates.
• Distribution Mechanisms: Manual, scheduled, and perpetual token issuance strategies.
• Groups & Authorization: Multi-party authorization and voting mechanisms for managing tokens.
• Example Data Contract: JSON schema illustrating token creation and configuration.

Also adds new, token-related endpoints

Preview build: https://dash-docs--101.org.readthedocs.build/projects/platform/en/101/docs/explanations/tokens.html