GOG GALAXY 2.0 updates and known issues

Known issues:
- All Games view - some games may appear as “Unknown” in the games library
- All Games view - Grid view - scroll performance is subject to significant improvement in upcoming releases
- Syncing bookmarks between devices doesn’t work yet
- Certain features from GOG GALAXY 1.2 are still missing (launching games with parameters)

Windows:
- Added jump list
- Back and forward mouse buttons now supported for history navigation everywhere

Updater:
- Will no longer download updates at startup, they will be downloaded in the background while the application is running
- [Windows] No additional UAC prompt during update

GOG Games:
- Brought back the ability to view the screenshot folder for GOG games
- Brought back the ability to download GOG Extras directly from GOG GALAXY 2.0
- Brought back the ability to view patch notes for GOG games
- Brought back information about manual updates being available for download

Integrations:
- Allow integrations to close their respective client after a game is exited
- Allow integrations to import tags from their respective platform
- Allow integrations to control whether GOG GALAXY 2.0 should treat a game as installable/playable
- Revamped the integrations settings window - added the ability to search for integrations

Manually added games:
- Fixed a bug where game time would sometimes not be correctly counted for manually added games

Global Search:
- Global Search can now be opened while viewing the store

Library:
- Multiple owned copies of the same game are now stacked into one. Switching between copies is possible with a new button on the game view.

- Added generic covers for games lacking cover art

Sidebar:
- 'Downloads' sidebar item becomes purple when there are unseen downloads
- Improved readability on sidebar count badges (All games, Friends online, etc)