Clean up max size spot orders

[JonRay15]

The Chore

Need to set the max size on teh slider for spot markets so that it accounts for the fees that will be paid on that order.

Acceptance Criteria

• [ ] The size slider max should take a conversative estimate of the max size and add on the total fee estimated for that size
• [ ] It is fine if this leaves behind a small balance in the general account
• [ ] We should add a warning if you are close to / over the max amount similar to what we have on futures / perps where we warn that you dont have enough margin, but just refer to the available balance of the asset not the margin
• [ ] If you try to make a trade that you dont have enough balance for it just fails silently, we should be getting a rejection toast I would think.

Additional details / background info