Arvados » Arvados Workbench 2

As a user I would like to have possibility to add/delete tag from collection
so that I will have possibility to improve managing and searching of collection

Acceptance criteria:
- user has possibility to add tag made from "Key" and "Value"
- deleting tags is available
- chips are composed of "Key"and "Value" separated by colon
- after adding a tag, snackbar appears

User flow (Adding a tag):

1. Specify "Key" and "Value" inside inputs

2. Click "Add" button

3. Tag was added to list and snackbar appears with notification that "Tag has been added"

User flow (Deleting tag):

1. Click on "x" icon inside chips

2. Popup appears with confirmation

3. Click "delete tag"

4. Popup appears with notification that "Tag has been deleted"

Mockup: https://3czrf1.axshare.com/#g=1&p=4_4_collection&c=1