Clean up dependence on type param for iOS builds

[janpio]

iOS builds are dependant on the type param right now as they are used to get the correct certificate for a build:

https://github.com/ionic-zone/fastlane-plugin-ionic/blob/master/lib/fastlane/plugin/ionic/actions/ionic_action.rb#L52

[janpio]

This is related to #12

Because of this right now one has to build for development this way right now:

    match
    ionic(
      platform: 'ios',
      release: false,
      type: 'development'
   )

[janpio]

Possible solution:

If release == false => type = development || param[:type]
When build with --debug, set type to development or any supplied value

[janpio]

More thoughts:

Official documentation of the packageType param this fills:

--	--	--
Packaging Type	--packageType	This will determine what type of build is generated by Xcode. Valid options are development (the default), enterprise, ad-hoc, and app-store.

release can be true or false for the plugin (which corresponds to --release and --debug on the CLI).

Default value right now is app-store: https://github.com/ionic-zone/fastlane-plugin-ionic/blob/master/lib/fastlane/plugin/ionic/actions/ionic_action.rb#L173

So it would make sense to do this:
release:true -> app-store
release:false -> development

[janpio]

Documentation of https://github.com/ionic-zone/fastlane-plugin-ionic/blob/master/lib/fastlane/plugin/ionic/actions/ionic_action.rb#L171 should be made clearer as well an mention that it also defines which certificate is used to build.