Show task progress while it is active

[axe312ger]

This pull request is based on #98. It should be merged first!

Display current task progress with percentage and estimated time to finish below the task. Verbose logging to CI should work pretty well.

The output of the progress observable might need a progress bar or other improvements.

Error display is not yet implemented and might cause visual issues with the update renderer, this needs some more work :)

Also, i am pretty sure the observable code can be optimised.

Standard progress display

Verbose progress display for CI

[Khaledgarbaya]

@axe312ger what's up with this PR ?

[axe312ger]

We should discuss this, since the error output with the current error handling is broken.

Also, since getFullSourceSpace is kinda the only function used by contentful-export, we may move it to the contentful-export repo to ease up maintenance. Why? Because we are changing the API here, it is then Observable based and no more Promise based which will break custom implementations of contentful-batch-libs

--> https://github.com/contentful/contentful-export/search?utf8=%E2%9C%93&q=contentful-batch-libs&type=

[Khaledgarbaya]

LGTM, just one small comments, maybe @zcei can give more feedback on the Observable

[Khaledgarbaya]

can you also remove the "debug": true, it's so annoying when building

[axe312ger]

This is now fully implemented via listr itself, promises and awesome loops. All without RxJS. Closing this one and deleting the branch...