General match statistics endpoint

[hoersamu]

Should return an array with a row for each map with interesting data.

Proposed schema:

[
  {
    name:"Hill",
    totalGames:150,
    winsAllies: 60,
    winsAxis:90,
    avgMatchDuration: 78,
    // (additional data)
  },
  ...{}
]

[hoersamu]

not too important right now since i can extract the values in the BFF