add ENTER MARKET option

**Is your feature request related to a problem? Please describe.**
in the exchange, currently you have the option to select the market pair via `MY MARKETS` or `FIND MARKETS`. Both are less than helpful and both work on looking up a list of markets and then requiring a mouse select from that list.

An exercise in understanding how broken they are is to change all of the `MY MARKETS` to each of the `HONEST.XXX` then attempt to find all `HONEST.XXX` cross rates. The sorting does not work. Then you go to `FIND MARKETS` you type in quote currency `HONEST.BTC` and then asset `HONEST` you'd expect every `HONEST` mpa that begins with the word `HONEST` to pop up... it doesn't. Instead you have to explicitly type out the full pair name in the second box and wait for them to pop up one at a time

**Describe the solution you'd like**
1) make my markets and find markets actually work

2) just add a third category where I can type in the market I want and not have to deal with the sorting mechanism, the api call, and then the select by mouse. I just enter `HONEST.BTC:HONEST.USD` in a box and it works or tells me the pair doesn't exist - no lists required.

Start at the exchange UI entry points for MY MARKETS and FIND MARKETS, and reproduce the reported sorting and market-search behavior using the HONEST examples. Done means the existing market selection works reliably and a user can enter a pair such as HONEST.BTC:HONEST.USD and receive either the market or a clear nonexistent-pair result.

Written by the indexing model from the issue text.