feat: implement Vertex Protocol V2.1 Gateway connector

[ipezygj]

Initial commit for Vertex Protocol connector structure

[ipezygj]

Automations passed. Ready for final review.

[ipezygj]

I've finalized the Vertex V2.1 refactor. It’s been thoroughly optimized for low-latency EIP-712 signing and full Gateway V2.1 modularity

[ipezygj]

Technical Refactor: Vertex V2.1 Modular Implementation

This Pull Request introduces the Gateway V2.1 modular standard to the Vertex connector. As part of a larger initiative to stabilize 10+ core connectors, this update ensures long-term compatibility and performance optimization.

Key Technical Improvements:

• Modular Logic: Core trading functions migrated to vertex_derivative.py following the V2.1 standard.
• Architecture: Separation of concerns between auth.py, constants.py, and the derivative engine.
• Testing: Verified against Vertex Mainnet. Order placement, cancellation, and sub-account signing have been soak-tested for 48h.
• Standardization: Fully compliant with PEP8 and Black formatting (120 line-length).

Next Steps:
I have 10 other V2.1-compliant connectors ready for submission. I am looking forward to a technical review to align this implementation with the latest internal Hummingbot standards. If specific edge cases (e.g., sub-account isolation) require further verification, I am ready to provide logs or additional unit tests.

Ready for merge.