feat: better exception when table doesn't exist

[gforsyth]

Ibis supports datafusion as one of our backends, and we make use of datafusion-python in service of that.

One of the thornier issues we face right is that Datafusion returns Exception as the exception type when a table isn't found.

The exception message is more specific, but on the Python side, it is generally not a good move to catch a bare Exception -- and we're in the position of having to catch it, then parse the exception message, then continue as appropriate.

[ins] In [5]: from datafusion import SessionContext

[ins] In [6]: c = SessionContext()

[ins] In [7]: c.table("notatable")
---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
Cell In[7], line 1
----> 1 c.table("notatable")

Exception: DataFusion error: Plan("No table named 'notatable'")

conversely, attempting to look at a catalog that doesn't exist:

[ins] In [9]: c.catalog("nope")
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
Cell In[9], line 1
----> 1 c.catalog("nope")

KeyError: "Catalog with name nope doesn't exist."

That's much nicer.

Describe the solution you'd like
Either a datafusion-specific error message, or raise a KeyError (or some other more specific error type.

Describe alternatives you've considered
Catching and parsing, as described above, but it's suboptimal.

Thanks!