Add auto-completion of saved requests to commands like run and inspect

[talis-fb]

Enable auto-completion with saved requests. For commands such as run and inspect, when a user types , the system should complete with the names of saved requests.

That way, if user has a lot of saved request, the use of them turn easy.

Possible Solution/Implementation

Since the project utilizes Clap for managing the CLI interface, the proposed solution involves configuring or extending its features.

Auto-completing saved requests can be achieved by reading the NAME of all FILES in {DATA_FOLDER}/collections/. For linux the folder is $HOME/.local/share/treq/collections/.