Challenge system rework

[RDIL]

So, right now, it's clear that challenges are just a mess. They have multiple different locations that critical portions are stored, and as a result, they barely respect the proper rules that challenges should follow, as defined by IOI. It's clear this system needs to be re-worked in a way that doesn't have the same flaws as the current one. Hoping to use this discussion as a way to provide a forum for talking about the new design.

Some problems the current one faces:

• Data is duplicated across both memory and between different storage mediums
• Scopes ignored
• Different formats get quickly confusing

[moonysolari]

These three requests ought to have exactly the same data in the listed fields in their responses:

• data.ChallengeData.Children of /profiles/page/DebriefingChallenges,
• data.ChallengeData.Children of /profiles/page/Planning,
• Data.Children of /authentication/api/userchannel/HubPagesService/GetChallengeTreeFor.

So it is natural that the implementation of all three should call the same function to get this data. However, it is currently not the case:

• /profiles/page/DebriefingChallenges and /authentication/api/userchannel/HubPagesService/GetChallengeTreeFor use the getChallengeTreeForContract function.
• /profiles/page/Planning uses the getChallengePlanningDataForContract function, which calls the reBatchIntoSwitchedData function.

I took a look and there is quite a lot of code duplication between the two implementations. Refactoring this will likely fix #66 because the problem did not occur for debriefing challenges, in whose implementation I used the getChallengeTreeForContract function.