Add ability to manage fees for a given billing account

[ajefts]

Provide an API to manage creation and editing of challenge fees on a billing account.

[ajefts]

@skyhit Can you setup a challenge for this one?

[skyhit]

@ajefts I will work on this. how does the challenge fees originally set?

[ajefts]

Right now we use an admin page in Direct to set them. We can set a % that applies to all challenge types, or fixed amounts per challenge type.

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On Wed, Sep 6, 2017 at 10:05 PM, skyhit ***@***.***> wrote: @ajefts <https://github.com/ajefts> I will work on this. how does the challenge fees originally set? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#4 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADorrttG5xNz6lkCvmdc8iFaQbJjBo5dks5sf09_gaJpZM4LrMt2> .

[skyhit]

@ajefts here is the challenge spec - https://www.topcoder.com/direct/contest/detail?projectId=30059282

more questions as following

1. do we need a GET endpoint or DELETE endpoint.
2. Should we apply security check for user role?

[ajefts]

@skyhit Spec looks good overall. We don't need a delete, but we should have a GET.

for security check, let's limit it to the administrator (via the v3 roles api) role for now.