Bare Minimum Barely tested code for now.

* look at `delegatedBalance` instead of `balance` in the TzKT API query
  results
* do not include bakers' fees as reward as discussed in issue

delegatedBalance is deprecated, need to sum up `own` and `external`
instead

also made a note that `currentDelegatedBalance` of delegators is also
deprecated

TzKT offers own_delegated and external_delegated values. We pass them
both to the reward calculation function.

OWNER_PARENT is the baker's reward. It's named this way because it can
split into children rewards when the bakery has several "owners" and
"founders" (maybe we should also deprecate this functionality). Now, we
populate this value straight from tzkt.

We also use it to calculate the ratio. There is a sanity function that
ensures that the sum of itemized balances and the total from tzkt are
"almost equal". This apparently is still passing.

With these changes, I see more realistic values in my caculations:
values are lower than with main branch, which makes sense, because the
stake has now increased.

Also, for my baker, almost all balance is staked, so I only keep an
amount of delegation rewards approx. equal to my delegation fee. In
contrast, before AI, I would keep my fee plus my own rewards, which now
go almost exclusively to the staking balance.