[DriveSetup] various issues

[diver]

In this video a user is very confused by DriveSetup and runs into all sorts of issues with it.

​https://youtu.be/2jdmcLHU3Vw?t=266

Here are some of the issues I spotted:

• <empty or unknown> should probably be renamed to Unallocated.
• creating a bfs partition should format it to bfs at the same time
• when creating a partition Active partition flag is not saved (​https://youtu.be/2jdmcLHU3Vw)
• it is not clear that "(Be File System)" in File system column means type and not actual file system.
• creating a partition doesn't show "Active partition" checkbox (​https://youtu.be/2jdmcLHU3Vw?t=493)
• Intel Partition Map disappeared after reboot and became GPT instead (​https://youtu.be/2jdmcLHU3Vw?t=1055)
• creating Partition Map recovered previous partitions instead of creating new layout (​https://youtu.be/2jdmcLHU3Vw?t=1109)
• don't disable Format menu if a volume is mounted but can be unmounted