./gno.land/{pkg,cmd}/gnoland: use a logger and remove commands.IO

[moul]

Context: #999 (comment)

• Instead of using commands.IO, gnoland should use a logger. The main purpose of gnoland is to log information, not to interact with stdin or write raw stdout/stderr. Using a logger is more suitable and allows for clear unit tests without the need for monkey patching.
• For other binaries, particularly CLI tools, we should assess whether the logger should be used more extensively in place of commands.IO. Alternatively, we can explore the option of commands.IO incorporating the logger or simply passing both more frequently.
• Bonus: The gnoland binary should not have access to os.Stdin. We can use build tags to configure os.Stdin as a noop reader.

Thanks to @piux2 for highlighting the need for this change.