Trezor Model T Hardware Wallet Support

**User Story**
As a `Trezor Model T user` I want an implementation to `support BitShares accounts` so that I may `safely store my private keys, sign transactions and submit them to the network`.

**Additional Context**
- [ ] #1339 Hardware Wallet Support (General)
- [ ] [Deterministic key hierarchy for Graphene-based networks](https://github.com/satoshilabs/slips/blob/master/slip-0048.md)
- [ ] [Registered Coin Types for BIP-0044](https://github.com/satoshilabs/slips/blob/master/slip-0044.md)
- [ ] [Developer Guide](https://wiki.trezor.io/Developers_guide)

## CORE TEAM TASK LIST
- [ ] Evaluate / Prioritize Feature Request
- [ ] Refine User Stories / Requirements
- [ ] Define Test Cases
- [ ] Design / Develop Solution
- [ ] Perform QA/Testing
- [ ] Update Documentation

Start by reviewing the general hardware-wallet issue #1339, the SLIP-0048 and BIP-0044 references, and the Trezor Developer Guide. The issue provides no files, tests, or entry points, so requirements and test cases must be defined before implementation. Done means BitShares accounts on Trezor Model T can store private keys, sign transactions, and submit them to the network, with documentation updated.

Written by the indexing model from the issue text.