Internal currency integration

# we will send the following header on all relevant requests
x-api-key: YOUR_API_KEY

GET <URL can be specified, e.g. https://api.domain.com/api/balances>

Query parameters:
{
  walletAddress: string | string[],  // case-insensitive
  startingAfter?: string // optional, only if pagination is required.
}

// no pagination
Status code: 2**
Response body:
{
  "data": [{
    "id": string // optional, only if pagination is required
    walletAddress: string
    amount: string // important: amount must be a string
    loyaltyCurrencyId: string
  }],
  hasNextPage: boolean // if pagination is required
}

POST <URL can be specified, e.g. https://api.domain.com/api/balances>

Body parameters:
{
  entries: [
		{
		  walletAddress: string // case-insensitive
		  direction: 'debit' | 'credit'
		  amount: string // important: amount must be string.
		  idempotencyKey: string | undefined // external client responsible for saving only once
		  metadata: Json | undefined
		}
	],
	description: "description of event",
	loyaltyRuleId: uuid | undefined
}

Response:

Success:
Status code: 2**

Failure:
Satus code: 4** or 5**
Response body:
{
  message: string
}

GET <URL can be specified, e.g. https://api.domain.com/api/entries>

Query parameters:
{
  walletAddress: string,  // case-insensitive

  // If passed in then filter by this value
  // return only the most recent per each rule.
	userCompletedLoyaltyRuleId: string | string[],

  // id from previous request, optional, if pagination is required.
  startingAfter?: string

  // number of elements to return
  limit?: int
}

// sorted by createdAt desc
Status code: 2**
Response body:
{
  "data": [{
    "id": string // optional, only if pagination is required
    walletAddress: string
    direction: 'debit' | 'credit'

    // we need this to determine if rule was completed
    idempotencyKey: string | undefined

    metadata: Json | undefined

    loyaltyRuleId: string | undefined
    amount: string // important: amount must be a string
    loyaltyCurrencyId: string
    description: string
    createdAt: datetime
  }],
  hasNextPage: boolean // if pagination is required
}