Add support for viewing times past the top 100

[ijust-dev]

On a map leaderboard page, you are only able to see the top 100 TP and Pro times. This is a limitation of the API. if you query more than 100 users, some usernames will appear as "null", as the API caches Steam names. This is also why names don't update immediately. Adding an extra arrow to move forward/backward 100 positions could resolve this limitation.