Update snapcraft./yaml for v18.07

Fix desktop file for Linux portable zip.

Update all translations for release.

Update snap for v18.05.08

Revert "Hide the gif format and codec."

This reverts commit 3397088.

Add Mosaic filter.

Fix opus link error on mingw64 build.

Add a Mask video filter.

Update all translations for release.

Update snap for v17.11