[C++/Python] Document how to provide information on segfaults

[asfimport]

We often have users that report segmentation faults in pyarrow. This will sadly keep reappearing as we also don't have the magical ability of writing 100%-bug-free code. Thus we should have a small section in our documentation on how people can give us the relevant information in the case of a segmentation fault. Preferably the documentation covers gdb and lldb. They both have similar commands but differ in some minor flags.

For one of the example comments I gave to a user in tickets see #2089 (comment)

Reporter: Uwe Korn / @xhochy

Related issues:

• [Python] Regression: segfault when reading hive table with v0.14 (is related to)

_{Note: This issue was originally created as ARROW-2652. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Seems like a smallish patch in developer/python.rst should do the trick. Does someone have experience with lldb (I only am familiar with gdb)?