Update to 50.0

This is a stable release with updated translations:

• Danish (Alan Mortensen)
• English (United Kingdom) (Bruce Cowan)
• Japanese (小山田 純 - Oyamada Jun)
• Occitan (post 1500) (Quentin PAGÈS)
• Polish (Victoria)
• Portuguese (Hugo Carvalho)

Update to 50.rc release

This is an unstable release with the following changes:

• Remember window size between app restarts
• Updates page could be sometimes hidden after resume from suspend
• Allow remove also Flatpak remotes from system installation
• Correct check for add-ons when app's ID changed
• Improve socket permissions checks for Flatpak apps

This release also updates translations:

• Basque (Asier Saratsua Garmendia)
• Catalan (Jordi Mas, Victor Dargallo)
• Chinese (China) (luming zh)
• Czech (Daniel Rusek)
• Finnish (Jiri Grönroos)
• French (Lucien Ouoba, Guillaume Bernard)
• Galician (Fran Diéguez)
• German (Christian Kirbach)
• Greek, Modern (1453-) (Efstathios Iosifidis)
• Hungarian (Balázs Úr)
• Interlingua (International Auxiliary Language Association) (Emilio Sepúlveda)
• Italian (Davide Ferracin)
• Japanese (Makoto Sakaguchi)
• Kazakh (Baurzhan Muftakhidinov)
• Korean (Seong-ho Cho)
• Spanish (Daniel Mustieles)
• Swedish (Anders Jonsson)
• Turkish (Sabri Ünal)