Frontpage rework

[B-i-t-K]

API: added two new queries.

• ctfsByDate(year:int, month:int) return all the CTFs taking place during a specific month
• `ctftimeCtfById(id: number) return the CTF information from CTFTime (manager+ only)

UI change:

• removed incomming/past CTFs and calendar page, instead use a by month display
• removed import CTF dialog, instead use the same dialog as edit, the CTFTime input now has a button to refresh the informations.
• The front page should be responsive, I've tested on my device but more tests are welcome.

Routing:

• removed: /ctfs/incomming, /ctfs/past, /ctfs/calendar
• added: /ctfs/:year?/:month?

Added dependencies:

• V-calendar: quasar calendar is too primitive for what I'm doing now

Do we want to remove ImportCtf mutation and IncommingCtf PastCtf queries in the future?