Remove line keys on all keys : by default it now displays a blank BLF key.
The phone configuration is now generated with its keys defaulting to BLF type with a %NULL% value. We couldn't use the options
- features.auto_linekeys.enable = 1
- along with account.X.number_of_linekey = 1 because it causes (at least what I observed) the phone to generate a local configuration with NULL line keys for all keys. It then would prevent configuration from server to be applied (because of parameter auto_provision.custom.protect = 1).
The fix implemented now sets every linekeys to BLF type (16) with %NULL% values except for the first line key on which we display the line (not mandatory, but probably better looking this way).
Closes #514