Support running other command line tools

[kmturley]

There are various command-line tools which can help with plugin and package management:

• Steinberg validator - Check your plug-in for VST 3 conformity
• clapinfo - Show information about a CLAP plugin
• pluginval - Cross platform plugin testing and validation tool

If they are useful for plugin developers, we could consider supporting them to make plugin development and publishing easier.
We may be able to extract package metadata from plugins directly to make the process of filling out package metadata easier.