fix(paths): add os specific directory handling for windows

[0Ky]

Adjusted the path generation in get_results_dir_path, handle_main_command, and setup_terminal functions to account for Windows-specific local config directory conventions using the cfg! macro.

This PR closes issue #37.

Below are paths for both the config & results files by OS.

Config file:

Windows: C:\Users\{Username}\AppData\Local\donkeytype\donkeytype-config.json
Linux: /home/{Username}/.config/donkeytype/donkeytype-config.json
MacOS: /Users/{Username}/.config/donkeytype/donkeytype-config.json

Results file:

Windows: C:\Users\{Username}\AppData\Local\donkeytype\donkeytype-results.csv
Linux: /home/{Username}/.local/share/donkeytype/donkeytype-results.csv
MacOS: /Users/{Username}/.local/share/donkeytype/donkeytype-results.csv

[radlinskii]

Looks really clean 👏 Did you test it on Windows?

[0Ky]

Looks really clean 👏 Did you test it on Windows?

Running cargo test passes.

test result: ok. 20 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.05s

I've also conducted tests manually on Windows OS, the donkeytype-results.csv file is generated at the expected path after completing a type test and adding donkeytype-config.json file to the same path with custom configuration is interpreted correctly.