Add basic CLI for configuration

[ByteOtter]

What does this PR change?

This PR adds a very rudimentary CLI using the clap crate.

This CLI enforces the use of at least two arguments:

netbox-sync --uri <NETBOX_URI> --token <NETBOX_API_TOKEN>

TODO:

• Accept (optional) uri and token arguments (string) from the CLI.
• Pass arguments on to the config_parser module.
• Overwrite the parameters read from the configuration file in the conf_data object.
• Error handling: If no config file exists and no arguments are passed -> exit.

Hint: The panic on an empty config file is in the main.rs and will change when the CLI is fully fleshed out. Until now, we need to fill the config file with something so it doesn't.

Furthermore planned are these two options:

• --no-config : Do NOT write a default config file and rely on the two arguments (may also be --write-config)
• --set-config <URI> <TOKEN>: Overwrite the two config parameters in the config file.

Tick the applicable box:

• Add new feature
• Security changes
• Tests
• Documentation changed

• General Maintenance

Links

Fixes: #22

• DONE

Documentation

• Documentation provided by buildable docstrings.

• DONE

[SchoolGuy]

@ByteOtter Is the PR ready for review? It is still in draft state.

[ByteOtter]

@ByteOtter Is the PR ready for review? It is still in draft state.

Sorry missed your comment. Should be ready now.

[SchoolGuy]

LGTM.