Add ability to download bundle (.aab file)

[DenisBalan]

Adding download of .aab application file for Android.
pre:

> docker run --rm -it node /bin/bash
(in container)
> npm install -g appcenter-cli
> appcenter login --token user-token

tested

> appcenter build download -i 1337 --app ORG/APP.Android -t bundle --debug
(output)
Downloaded content was saved to /tmp/bundle_APP.Android.aab

[AnatolyPristensky]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[AnatolyPristensky]

Hello @DenisBalan, thank you for your contribution!
Unfortunately CI with your changes is failed with the following error:

/home/vsts/work/1/s/src/commands/build/download.ts
107:29 error Delete · prettier/prettier

Could you please have a look?

[DenisBalan]

@AnatolyPristensky done

[AnatolyPristensky]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).