feat: (daemon) saves default RPC token and (CLI) consumes it automatically

[hanabi1224]

Summary of changes

Changes introduced in this pull request:

• update daemon to save RPC token to {data_dir}/token by default, to align with Lotus
• update CLI to consume the default token

Reference issue to close (if applicable)

Closes #4745

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

[LesnyRumcajs]

Let's have a changelog entry. Also, can any of the pages or existing scripts be simplified thanks to this?

[hanabi1224]

Let's have a changelog entry. Also, can any of the pages or existing scripts be simplified thanks to this?

@LesnyRumcajs changelog, scripts and docs are updated.