User menu if there are multiple possible cards found

```
!ruin
t=2019-01-26T17:08:03-0600 lvl=dbug msg="In lookupUniqueNamePrefix" C="[Ruin Ghost Ruin Processor Ruin Raider Ruin Rat Ruin in Their Wake Ruination Ruination Guide Ruination Wurm Ruinous Gremlin Ruinous Minotaur Ruinous Path Ruins of Oran-Rief Ruins of Trokair]"
```

Currently a request like this just fizzles, because there's Too Much Stuff and none of them match the legendary-ish fuzziness.

Suggestion: add per-user menus if multiple things come back and we can't make a reasonable guess. Ex:

```
teysa
-Datatog- 4 cards beginning with "teysa" found: (1) Teysa Karlov (2) Teysa, Envoy of Ghosts (3) Teysa, Orzhov Scion (4) Teysa, Orzhov Scion Avatar
```

Start at the lookupUniqueNamePrefix path shown in the debug output and trace how multiple card matches are handled for an IRC request. Implement a per-user response when no reasonable match can be selected, following the numbered Teysa example; done means ambiguous lookups present selectable matches instead of fizzing.

Written by the indexing model from the issue text.