Use ENV vars to login with CLI helper

 - OSDB_LOGIN
 - OSDB_PASSWORD
 - OSDB_LANG
Build Subtitle{} by inspecting movie & sub files
Reformulate comments
Subtitle to subtitle upload params
Fix methods to try subtitle upload

Fix `HasSubtitles`, because it did not work, and sent messed up XML-RPC
parameters to TryUploadSubtitles.

Also, add `HasSubtitlesForFiles(movie, subs)` to easily build up the
required Subtitle type that `HasSubtitles` expect.
Add "osdb put" command

For now, it does not upload anything, but rather tries to upload
subtitles, checking with OSDB whether they already have those...