model: make query_directory more straightforward

Add an enum_directory method which has the previous behavior
test:querydirectory: add test for enumerating with specific pattern
smb2: uncomment some create options

These can actually be returned in FileModeInformation
model: make query_file_info return info instead of SMB2 header
test:durable: mark tests as requiring lease cap
test:readwrite: add more tests around 0-byte writes