Enable passing babel-plugin-react-intl options.

[Filson14]

Do you want to request a feature or report a bug?:
Feature

What is the expected behavior?:
I have a case where I've wrapped react-intl with my own module with some custom functions and components to manage internationalization. I don't want the need to import some elements from it and some from react-intl. I prefer to use just one source. I've mentioned it in this issue.

babel-plugin-react-intl accepts few options to manipulate extracting process. With extract-react-intl context, most of them are not so helpful (especially if we assume using it with by extract-react-intl-messages), but one is. I mean moduleSourceName which lets plugin to know from where defineMessages or <FormattedMessage /> is imported. Of course, default is react-intl but in some cases one may want to use custom module.

Suggested solution:
It would be great to be able to pass custom module name to extract-react-intl which can forward it to babel-plugin-react-intl (I've tested it locally, simply by explicitly adding options to unshifted preset in the source code and it works).

Same thing would fit extract-react-intl-messages.

@akameco, I can try to manage some changes if you want (but never done that on someones github repo 😉 ).

[akameco]

@Filson14 Sounds good. Could you send a PR?

[Filson14]

Done in here #20
I wait for Your thoughts.