bottle: favour system-wide version over in-house version
as reported in #97 (closed) our version of bottle.py is not compatible with python 3.10. this merge request started as an attempt to replace our in-house version of the module with the version supplied by the reference OS, to shift maintenance responsibility to the package maintainer. the changes are:
- from gstlal import bottle --> import bottle
- catch ImportError exception to fall-back to internal version
it has been found the version supplied by the reference OSes is missing features that we require.
Edited by Kipp Cannon