* Move State property from activePlugin to PluginHealthStatus. env.activePlugins is now reserved for healthy running plugins.
* Add comments for function declarations
* Combine activePlugins and pluginHealthStatuses into a common structure, registeredPlugins
* Add check to see if plugin is active before deactivating it
* Make `Deactivate` set plugin status
* Add comment explaining the `registeredPlugins` map
* Give responsibility to set plugin disabled status upon deactivation back to `env.Deactivate`
* check if plugin needs to be deactivated before setting status