LPS-44312 Fix NPE when adding new files to DM
LPS-44312 Rename FileEntryChecker to FileEntryDisplayModel
LPS-44312 Remove unused constructor (it will be added in later commits)
LPS-44312 Move isFileEntryLockedByMe to FileEntryDisplayModel because it's part of the model (same as hasLock() method)
LPS-44312 FileVersion can be null only if file entry is null, otherwise it may through NPE so we are throwing IllegalArgumentException in that case
LPS-44312 Rename FileEntryDisplayModel to FileEntryDisplayContextHelper
LPS-44312 Sorting
LPS-44312 Rename isFileEntryLockedByMe() to isLockedByMe() because the rest of the methods don't have the FileEntry prefix
LPS-44312 SF