Make names of extension's folder and zip file more descriptive (for releases)

[trnstlntk]

I just did the 0.1.0 release of this extension. When following the process in our README.md the resulting zip file and folders have names that are undescriptive or too vague; it would be good to make sure these get more descriptive names for upcoming / new releases.

Currently the resulting .zip is named openrefine-commons.zip > I manually renamed it to openrefine-commons-extension-0.1.0.zip > would be good if zipfiles for next releases can use a similar naming scheme.

When unzipping, the encompassing folder is called module which is very non-descriptive > I renamed it to commons-extension > would be good to have this in the future too.

Old situation:

New (after my manual renaming):