Classify Trade Simulation Errors

[nlordell]

Currently, trade simulation errors are quantified as "Other" and lead to HTTP 500 errors if all estimators fail.

We should classify these errors separately and return a better error in these cases.

For example:

% curl -s http://localhost:8080/api/v1/quote -X POST -H 'content-type: application/json' --data '@-' <<JSON | jq
{
  "from": "0xf17afe5237d982868b8a97424dd79a4a50c36412",
  "sellToken": "0xdac17f958d2ee523a2206206994597c13d831ec7",
  "buyToken": "0x6b175474e89094c44da98b954eedeac495271d0f",
  "kind": "sell",
  "sellAmountBeforeFee": "1000000000"
}
JSON
{
  "errorType": "InternalServerError",
  "description": ""
}

[fleupold]

This issue will likely become irrelevant as part of the Verified Quotes initiative