pkgctl-version-setup: Automatically detect and setup a basic nvchecker config

This subcommand automates the creation of a basic nvchecker[1] configuration file (.nvchecker.toml) by analyzing the source array specified in the PKGBUILD[1] file of a package. This command intelligently detects various platforms and APIs (e.g., GitHub, GitLab, PyPI) used by the package sources and generates a corresponding .nvchecker.toml configuration based on its best guess.

This is particularly useful for initializing nvchecker[1] settings for a package without manually crafting the .nvchecker.toml file. It simplifies the process of setting up version checks, especially when transitioning a package's monitoring from one source platform to another or starting version checks for a new package.