Get latest version in Opera store (add locale metadata)

Opera store rejected v4.8.0 with the error `Detailed description missing for Russian.`.

I am not sure if this would continue to throw for other languages, or if there are other fields that need completion. This issue will represent completing all tasks required to get the latest version published on the Opera addon marketplace.

Start by reviewing the locale metadata used for the browser extension and the requirements for publishing on the Opera addon marketplace. Check whether every language has the required detailed description and other required fields, then verify that the latest version can be submitted successfully.

Written by the indexing model from the issue text.