[Feature] RPC: Filecoin.StateDealProviderCollateralBounds.

[ruseinov]

Summary of changes

Changes introduced in this pull request:

• introduces Filecoin.StateDealProviderCollateralBounds RPC endpoint

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation,
• 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.

[ruseinov]

Still not ready for review, just running CI.

[ruseinov]

Rename get_circulating_supply to get_state_circulating_supply.
Document the difference between get_vm_circulating_supply and get_state_circulating_supply.
Possibly move get_state_circulating_supply out of vm_circ_supply.rs as it's confusing.