Allow to stack cases in multiples mode

[boogheta]

• [ ] add interface checkbox in cases title when in multiples
• [ ] handle proper fields:

all tested = {
   tested negative
 + confirmed = {
      recovered
    + sick = {
         confined
       + hospitalized
       + intensive_care
    }
    + deceased
  }
}

adjust cases legend?

• [ ] use different level strokes to display contours