As a software engineer
I want combine verify and verify_hex into a single verify function and move it to crypto_service.rs
So that the code is simplified and an unnecessary dependency is removed  

Given that crypto_service.rs now handles sign and verify
When refactoring verify and verify_hex in signature_service.rs
Then combine verify and verify_hex into a single verify function (that takes hex strings)
And move the combine verify function to crypto_service.rs
And then delete signature_service.rs
And update dependencies to only need CryptoService from crypto_service.rs

Implementation Notes

- Place any unit tests at the bottom of the same file as the associated production code
- Increment patch version of anttp package in Cargo.toml
- Create a copy of this issue description and save to /spec using the name of this issue as the filename (with lower underscore case, starting with the 5 char padded issue number, e.g. 00001_issue_title.txt)
- Update unit tests to validate the changes

Amendments

- move verify_signature to within the CryptoService struct (with &self) and update dependencies