Added ability to filter on only games you onw in scheduled bookings

[x183]

fixes #96

• Adds endpoint /borrow/list/ownGames which returns bookings only on games owned by you
• Adds a checkbox in the frontend to switch between showing all bookings and only on your games
• Fixes a bug where scheduled bookings also showed past bookings

[x183]

I was not really sure if this warranted its own dedicated page or if we should just implement some kind of filter function on the scheduled bookings page @Krysset

[GAsplund]

IMO since it just modifies the same content it should be on the same page, much like the front page.