Merge pull request #14 from l/translation_ja

Update Japanese translations
Fix field with min/max WeeChat version in new script form
Update German translations
Update files with list of scripts after removing a script from database
Update files with list of themes after removing a theme from database
Remove translations for script opall.py (script removed)
Replace weecloud URL by link to GitHub page
Fix URL displayed for weecloud
Fix display of multiple tracker links on roadmap page
Use https for links to cve.mitre.org
Add alternative text for some images
Add alternative text for link images
Fix typo in a French translation