net/remmina and net/remmina-plugin*: Upgrade to 1.3.9

Also fix net/remmina-plugin-st:

• Remove duplicate icon installed by net/remmina-plugin-exec
• Include as default dependency of net/remmina-plugins

Changes this release:

https://gitlab.com/Remmina/Remmina/blob/v1.3.9/CHANGELOG.md