Configuration option to define the name for the principal branch

The current Git convention is changing the principal branch name from master to main but SmartGit always create the principal branch named "master". If user want to use a different name to the principal branch a rename action is required after repository is created.

Please, add a configuration option to permit user configure any preferred name for the principal branch, then when a new repository is created, the preferred name is used, instead master.

Thanks for your attention and support,