No real-time update support (yet) but this is the first draft at writing
trades ledgers and `pps.toml` entries for the kraken backend.
Deatz:
- drop `pack_positions()`, no longer used.
- use `piker.pp` apis to both write a trades ledger file and update the
`pps.toml` inside the `trades_dialogue()` endpoint startup.
- drop the weird paper engine swap over if auth can't be done, we should
be doing something with messaging in the ems over this..
- more web API error response raising.
- pass the `pp.Transaction` set loaded from ledger into
`process_trade_msgs()` do avoid duplicate sends of already collected
trades msgs.
- add `norm_trade_records()` public endpoing (used by `piker.pp` api)
and `update_ledger()` helper.
- rejig `process_trade_msgs()` to drop the weird `try:` assertion block
and skip already-recorded-in-ledger trade msgs as well as yield *each*
trade instead of sub-sequences.
Tyler Goodlet