[api] Asset Code Quote Memo, Fix Fuzzy Asset, Loan Quote Short Memo

Fixes the poor error response to the following:

https://thornode.ninerealms.com/thorchain/quote/swap?amount=100000000&from_asset=BTC.BTC&to_asset=LTC.LTC&destination=ltc1qzvcgmntglcuv4smv3lzj6k8szcvsrmvk0phrr9wfq8w493r096ssm2fgsw&streaming_interval=10&streaming_quantity=0&affiliate=a&affiliate_bps=0

It will now return generated memo too long for source chain, but in this case the memo fits with the short code. Temporarily deployed to dev for verification:

https://thornode.dev.ninerealms.com/thorchain/quote/swap?amount=100000000&from_asset=BTC.BTC&to_asset=LTC.LTC&destination=ltc1qzvcgmntglcuv4smv3lzj6k8szcvsrmvk0phrr9wfq8w493r096ssm2fgsw&streaming_interval=10&streaming_quantity=0&affiliate=a&affiliate_bps=0

Also fixes #1654 (closed).