Arvados » Arvados Workbench 2

As I user I would like to create a new collection
so that I can upload new files to application

Acceptance criteria:
- modal with fields appears
- user has to defice collection name (mandatory field), description (optional) and upload the files (mandatory field)
- at least one file is required to create a collection
- user has possibility to add/drag and drop folders with content
- will use upload component (https://dev.arvados.org/issues/13856)

User flow:
1. Click on "Create a collection" button in dashboard
2. Modal appears
3. Fulfill mandatory fields
4. Click "Create a collection"
5. Snackbar appear that collection is created.