Querying all HEASARC data/observations for a range of times for a particular mission

HI there,

I am coming back to astroquery after using version 0.4.5. In that version I was able to query all the data in a time range and then do additional filtering based on the field of view of the instrument that I am interested in (the BAT with a large FOV). I would do this like
```
heasarc = Heasarc()
queryargs = dict(time="2004-12-15..2006-10-27", fields='All', resultmax=0)
table = heasarc.query_object(object_name=None, mission="swiftmastr", **queryargs)
```

Looking through the documentation for the v0.4.11.dev274, it isn't clear to me how this translates to the changes API, even after trying some of the new functions. They all seem to rely on querying a point or a region in the sky. Is there a recommended way to query with respect to time and not a coordinate?

Start with the HEASARC documentation and the Heasarc query API, comparing the older query_object call using mission="swiftmastr", time, fields="All", and resultmax=0 with the v0.4.11.dev274 functions. Determine whether a time-only query is supported without a coordinate and consider the issue done when the supported call or limitation is documented clearly.

Written by the indexing model from the issue text.