Add "draft" release status

[Sisind]

The Google Play Developer API supports different release statuses. [1]

It would be nice to be able to set the release status to draft.

1. To be able to setup the CI on projects that have not been finished yet.
2. To generally support a wider range of project types.

An easy way would probably be to use the custom tracks similar to:
Setting the status to "inProgress" when the Track is called "rollout". [2]
Pros and Cons of the easy way:
Pros:

• easy to setup
• no need to change the GUI
  Cons:
• bit of a hack as it is not intuitive
• not easy to find if not stated in the README.md

[1] https://developers.google.com/android-publisher/api-ref/rest/v3/edits.tracks?hl=en#status
[2]

BambooGooglePlayPublisher/src/main/java/com/drextended/gppublisher/bamboo/util/AndroidPublisherHelper.java

Line 302 in 41ed24b

if (TRACK_ROLLOUT.equals(trackName)) {

[Sisind]

@drstranges I'm no Java developer, but I have added the changes locally, that I think would be required.

If you could tell me how to generate a pull request I can show you the changes.
As far as I can tell I am not allowed to push to a new branch in this repo.

[drstranges]

@Sisind It would be great if you could make PR from your fork. I found this instruction for that. https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request-from-a-fork