order_mode further UX refinement ideas needing feedback

[goodboy]

Follow up to initial work in #205.

This is an (appendable) set of UX changes that would likely improve (manual) use of order mode / chart trading:

• on order submit, currently the staged line graphic is submitted to the chart immediately. when the order is modified the line is moved immediately and after a submission ack is received the level marker is added only after we get back a response confirming the EMS submission. Some alternative UXs might be:
  • the order line is staged with the color of the action (green, red, yellow) but once the user clicks we change the color to something nuetral (like gray?) and then once the submission-ack is received we flip back to the original action color.
  • when modifying the order line something similar could be done, we stage a gray line which tracks the mouse-click-n-drag and only move the original line once we get the EMS ack-back. this would be a more clear indicator how how live an order is and what kind of touch-and-feel latency the broker is presenting for manual trades.
• the new Allocator position limiting system currently prevents a user from entering too large a pp - past what they've configured for themselves ahead of time. the current mechanics of this limit are that the next staged order (after the limit has been hit) will submit a 0-sized order to the EMS (which is in turn directly relayed to the corresponding brokerd for live submissions) . there's a few open questions about how we could adjust this (and maybe offer config options for different preferences):
  • we could simply not show a staged order line (and maybe a warning status message?) if there are no more slots to fill
  • we could FIFO drop the oldest submitted order in the case where we aren't yet at a full slot count but if all submitted orders were filled we'd be over (this is what TWS seems to do)
  • consider in detail how to handle orders which are conditional (such as cancel group orders or fishing orders) -> this will become something very serious to consider once we have inter-coupled group trade allocator algos working in tandem