ij-ui-swing-updater: fix base package declaration
Fix reflected package names

Of course, these are all bad anyway (hence the FIXMEs), but
for now, they at least need to reference the correct FQCNs!
Rename LUTSelectorPlugin to LUTSelector

The "Plugin" suffix is discouraged, as there are many types of
plugins, and specifically, the LUTSelectorPlugin is a Command.