Displaying in Translations manager the ini files from extensions
language folder
Allowing plugins .sys.ini files to be loaded to translate.
oops
Correcting path to extensions language folders
Preventing plugins containing language folder to be displayed when
filtering by site
Merge pull request #223 from infograf768/ext_package_choice

Correcting path to plugins language folders
Merge pull request #222 from infograf768/extensions_translate

Displaying in Translations Manager the ini files from plugins' language folder