Prevent duplicate holiday requests

[jekuno]

OBSERVED

• Currently when making a vacation request the calendar allows me to select and request days which had already been approved before.
• If an already approved day gets approved again the public calendar shows two entries for me at that day.

EXPECTED

• Days which already have been approved are highlighted green and cannot be requested again.
• Days which already have been rejected are highlighted red (but maybe can be requested once more).