allow plugin-name short aliases in cli

Instead of forcing/telling users to type:

	Console/cake PluginName.plugin_name

Allow:

	Console/cake PluginName

And:

	Console/cake plugin_name

Also be case insensitive/consistent when resolving aliases
move adding short plugin aliases to constructor

That way, they are always present, and don't prevent/interfere with a
user creating their own command aliases
Merge pull request #4364 from AD7six/3.0-cli-short-plugin

allow plugin-name short aliases in cli