(hack) Add bolt module show <module> command

[beechtom]

This adds a new bolt module show <module> command that shows detailed
information for a module. It lists the module's name, version, summary,
available plans and tasks, operating system support, and dependencies.

!feature

• Show detailed module information

  Bolt now supports showing detailed information about a module using
  the bolt module show <module> command and Get-BoltModule -Name <module> PowerShell cmdlet.

[lucywyman]

Suggested change

	raise Bolt::Error.new("Unknown module #{name}", 'bolt/unknown-module')
	raise Bolt::Error.new("Could not find #{name} on the modulepath. Use #{command} to install the module.", 'bolt/unknown-module')

Or something. I'm not sure users will know that this data comes from the modules on the modulepath and not the Forge, so mostly just want to clarify that.

[beechtom]

Updated. Left out the command suggestion since you can use a short module name (e.g. no author in the name), which doesn't work with the module add command.

[lucywyman]

• Errors if the module doesn't exist
• Accepts <namespace>/<module_name> syntax
• Accepts <namespace>-<module_name> syntax
• Accepts <module_name>
• Formats as JSON with the JSON outputter
• Formats a module with no metadata
• Shows the first module on the path (modules are shadowed)
• Gets module data locally, not from Forge
• Handles invalid JSON in metadata.json
• Has a nice message when a module exists on the Forge, but not the modulepath
• Shows a module that doesn't have plans or tasks
• Shows a project
• Includes powershell cmdlet
• Works when not inside a Bolt project
• Does not list private tasks and plans

I don't think there's a lot we can do to make this better and it doesn't seem that bad, but the invalid metadata output is definitely a little odd:

lucy ~/githubs/bolt ((7c8fe299...)) $ be bolt module show mymodule
mymodule has an invalid and unparsable metadata.json file. The parse error: 783: unexpected token at '{
  "invalid"
}
'
mymodule has an invalid and unparsable metadata.json file. The parse error: 783: unexpected token at '{
  "invalid"
}
'
mymodule has an invalid and unparsable metadata.json file. The parse error: 783: unexpected token at '{
  "invalid"
}
'