Files data card

[ptbrowne]

• The permission "io.cozy.files" triggers the showing of this card. This will surely change in the future. A workshop is planned on how to decide whether to display a datacard, see Choose a data card for a konnector #1275
• Shows the last 5 files imported by the konnector for the account that is shown
• A click on the file brings the viewer
• useRealtime is used so that the list of files is updated when the konnector
  imports data
• This functionality is in testing right now and the flag harvest.datacards.files
  needs to be set

Next steps:

• Add an animation for new items entering the list. This will make the realtime
  more obvious
• Repair the "running" button of harvest, right now, after reopening the modal,
  the state is not good
• Add tests. Since I was in an exploratory phase and since we do not know yet
  if this code will survive, I plan to add tests when the flag is removed.
• Use bills instead of files, this way we'll have the amount/date of the bill

Those steps will be done in a future PR.
This future is testable on the following adhoc build:

• git://github.com/cozy/cozy-home.git#build-files-datacard
• flag('harvest.datacards.files', true)

[Crash--]

It remains to put all the logic of certifications in the viewer directly since we don't redirect to Drive's viewer ^^.

Nice work

[Crash--]

👏