Enabled the Plugins menu and hid core modules.

Case/manifest.mf

CoreComponentInterfaces/manifest.mf

...c/org/sleuthkit/autopsy/corecomponentinterfaces/layer.xml

CoreComponents/manifest.mf

CoreUtils/manifest.mf

DataModel/manifest.mf

DirectoryTree/manifest.mf

ExifParser/manifest.mf

FileSearch/manifest.mf

HashDatabase/manifest.mf

Ingest/manifest.mf

KeywordSearch/manifest.mf

MenuActions/manifest.mf

RecentActivity/manifest.mf

Report/manifest.mf

Testing/manifest.mf

nbproject/platform.properties

thunderbirdparser/manifest.mf