Add workspace with lib and initial cli

[notmandatory]

Description

Create workspace with separate packages for the rust-cktap lib and a new cktap-cli binary. The cktap-cli project is just a skeleton with two commands partially implemented. Starts but doesn't finish work for #11.

Notes to the reviewers

One of the goal of the cli project is to present different help and commands depending on which card the user is using.

Changelog notice

• Move rust-cktap into workspace lib directory.
• Create skeleton cktap-cli binary also in workspace cli directory.

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo fmt and cargo clippy before committing

New Features:

• I've added tests for the new feature
• I've added docs for the new feature

[notmandatory]

@brh28 I fixed the CI issue by changing the workspace to exclude the cktap-cli project if building for the MSRV. I really only care about the MSRV for the rust-cktap lib. It's a bit of a hack but no better way right now besides not using workspaces at all, and most users will be using stable rust and then it's nice to have everything in a workspace.

[brh28]

I follow the basics of what you're saying but don't know enough about MSRV to offer any insight, so no issues from my end

[brh28]

ACK ed25c61