"humanize" should return "end of tomorrow" instead of "two days"

## Feature Request

```py
import arrow
import datetime

now = arrow.get()
print(now.humanize())

day = datetime.timedelta(days=1)
tomorrow = now + day
print(tomorrow.humanize())

end_of_tomorrow = tomorrow.replace(hour=23, minute=59, second=59)
print(end_of_tomorrow.humanize())
```

This prints

```
just now
in a day
in a day
```

It would be nice to be able to configure `arrow.get(...).humanize` to print something like:

```
just now
tomorrow at XPM
end of tomorrow
```

Similarly, it might be nice to get `"Wednesday"` instead of `"in two days"` (if today is e.g. Monday) via some fiddly knob.

Start at the arrow.get(...).humanize entry point and reproduce the supplied example with the current date and time behavior. Clarify the desired configuration for end-of-tomorrow and weekday wording, then add coverage showing the requested output once the behavior is specified.

Written by the indexing model from the issue text.