* Create the FeeSettings object in genesis ledger.
* Initialize with default values from the config. Removes the need to
pass a Config down into the Ledger initialization functions, including
setup().
* Drop the undocumented fee config settings in favor of the [voting]
section.
* Fix#3734.
* If you previously used fee_account_reserve and/or fee_owner_reserve,
you should change to using the [voting] section instead. Example:
```
[voting]
account_reserve=10000000
owner_reserve=2000000
```
* Because old Mainnet ledgers (prior to 562177 - yes, I looked it up)
don't have FeeSettings, some of the other ctors will default them to
the config values before setup() tries to load the object.
* Update default Config fee values to match Mainnet.
* Fix unit tests:
* Updated fees: Some tests are converted to use computed values of fee
object, but the default Env config was also updated to fix the rest.
* Unit tests that check the structure of the ledger have updated
hashes and counts.
The amendment increases the maximum sign of an account's signer
list from 8 to 32.
Like all new features, the associated amendment is configured with
a default vote of "no" and server operators will have to vote for
it explicitly if they believe it is useful.
