Dialplan not generated when IVR sound files are not ascii

When you add a sound file with a special caracter (ex: `ç`) and assign it to an IVR
When you reload Asterisk

Then the dialplan fails to load

This is the traceback I’m getting in wazo-confgend

My feeling is that wazo-confd should not allow file names to contain non ascii characters but maybe we could also fix confgend to be able to generate extensions.conf and test if it actually works with Asterisk