Soxs

This version of SOXS fixes two bugs.

* For certain instruments, in particular the *Lynx* LXM varieties, instrumental
background simulations were yielding no events because of how the files were
being read. This bug has now been fixed.
* Custom instrument files that were not part of the official SOXS instrument file
registry, but placed in the `soxs_data_dir` location, were not being properly
detected. This bug has been fixed. Thanks to [xshaokun](https://github.com/xshaokun)
for pointing this out in [GitHub Issue 38](https://github.com/lynx-x-ray-observatory/soxs/issues/38).

* Spatial region handling in the context of `soxs.events.filter_events` and
`soxs.events.write_spectrum` has been fixed for composite regions which
mixed regions which include and exclude data.
* When creating spectra using `soxs.instrument.simulate_spectrum` and
including backgrounds, the square root of the ``bkgnd_area`` parameter was
used to normalize the backgrounds instead of the ``bkgnd_area`` parameter itself.
This has been fixed. Thanks to liuguanfu1120 for pointing this out in Github Issue https://github.com/lynx-x-ray-observatory/soxs/issues/36.
* The "SOXS Background Models" page incorrectly reported ``"wabs"`` as the default
absorption model for the Milky Way foreground, instead of ``"tbabs"``. This has
been corrected. Thanks to liuguanfu1120 for pointing this out in Github Issue https://github.com/lynx-x-ray-observatory/soxs/issues/35.

Fixes EBOUNDS channel indexing in LEM RMFs

* Fixes a bug in which it was impossible to create an exposure map for instruments
without dither.
* Drops support for Python 3.8.

Fix spurious warning in logger about instrument files

Fix bug in loading LEM response and update XRISM responses for AO-1