Resolve address from pointer before every read operation

As an AntFTP user
I want to resolve the pointer name to an address for each read operation
So that if the pointer address is changed by a prior write by any user, the latest archive address will be resolved 

Given any changes to an archive require the pointer content to be updated to the new public archive address
When a read operation occurs (get, list)
Then the pointer client should resolve the latest address for the connection
And libunftp::Server::with_anttp_pointer is provided a PointerServiceClient instead of the resolved address
And resolve_pointer function is moved from main.rs to lib.rs within the unftp-sbe-anttp crate

Given testing would improve quality
When adding pointer support
Then update the unit tests and integration tests to reflect the ability to pass in and update a pointer

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)
- Implement basic unit tests
