Improved artifact executable detection

This PR modifies the extractors for both `.zip` and `.tar`/`.tar.gz` files to inspect files within the archives, and runs descriptor (executable contents) detection on them, adding an additional datapoint for hopefully extracting correct binaries from said archives. Notably, this should fix failed extraction for a tool that: - Has a binary name that does not exactly match the tool name - Has no permission bits set (unix) - Has no executable suffix in its filename (`.exe`) A real-world scenario where such a thing would happen: 1. A tool at a GitHub repository `toolauthor/toolname` gets forked as `organization/toolauthor-toolname` 2. The tool only has `.zip` files as its release artifacts (no permission bits) 3. The tool has binaries for unix platforms (no executable suffix)