New BSR repository bundle type

[amis92]

There are two workflows when the user downloads all the files for the given repository:

1. First time download when the repo subscription is created.
2. Any other time when the user checks the Clear data checkbox.

With @Jonskichov we agreed it'd be an optimization to introduce a new bundle option for download, that'd download all the datafiles as a one file.

We're in the process of designing this, but a new field like repositoryBundleUrl in the RepositoryVm sounds reasonable.