instead of raising an exception (to be consistent with the rest of the api
eg. get_host_cluster()

fix passing None to a Remote's Process args stdout/err handler caused exception
due to not handling special case in substitutions

useful for having working cmdline completion in ipdb when ipdb is spawned
from a an execo script

[execo, execo_g5k, execi_engine] fix regexes thanks to python 3.12 improved handling of invalid escape sequences
(https://docs.python.org/3/whatsnew/3.12.html#other-language-changes)

[execo_g5k] planning: log level warn instead of detail for errors while getting data from oar db with sql

- canonical_host_name: fix for ifname != ethX (eg. fpgaX)
- add get_host_interface

- expect handler constructor takes process to be able to scan at init
- scanning code factorized between stdin / stderr events and constructor
- debug log
- allow passing an explicit expect_output_handler (instead of the default
  automatic thread local one) to the expect method for more control in
  specific situations
- protect from uninitialized thread local expect output handler

+ refactoring