[Resource] Flashcard resource

[WolfyWin]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no

• Initialise the new plugin and resource.
• Resource editor for adding/modifying/removing cards from the deck.
• Player with random draw of all cards in the deck.
• Home/end page option.
• Store seen, successful, failed cards.
• Display the number of cards seen, passed, failed on the Home and End Pages.
• Option to set number of cards to draw.
• Algorithm to prioritize unseen and failed cards.
• ResourceEvaluation.
• Content types.
  ...