Passing wp plugin activate a full plugin path

When building a vagrant for the devhub using VVV, I checkout Nacins handbook plugin:

```
svn co https://meta.svn.wordpress.org/sites/trunk/wordpress.org/public_html/wp-content/plugins/handbook/ htdocs/wp-content/plugins/handbook
```

Then attempt to activate it, however that folder has 2 plugins in it, and I'm only able to activate one of them using WP CLI. This is because they both have the name `handbook`, and WP CLI is only able to activate the first. Running the command again states it's already activated.

Instead, if I could pass in a command such as this:

```
wp plugin activate handbook/handbook.php
wp plugin activate handbook/functionality-for-pages.php
```

Then I could activate both plugins, without instructing the user to head to the plugin page to activate functionality for pages