Roll up all CLI's into one

The `wirecell-*` pattern for command line programs is not scaling well.  Try to find a way to make a single `wirecell` program that combines all mains into a unified command tree.  Eg so that

```
wirecell-util resolve
```

becomes

```
wirecell util resolve
```

With top level
```
wirecell
```
printing docstrings for all the main commands.