In some cases, it may be necessary to create a filesystem with specific features enabled/disabled.
This PR is a proposal of an API extension, making it possible to create filesystems this way. It does so by introducing a new m_Features member variable and the createWithFeatures() function to the FileSystem base class. The latter function is implemented for the btrfs and ext2/3/4 filesystems.
Additionnally, the CreateFileSystemJob has been modified to enable creating/formatting filesystems with specific features enabled.
Please note this PR should be considered *work in progress*: most filesystems lack a proper implementation, and it has not been thoroughly tested. However, it is open for discussion, and comments are more than welcome.