Removed caching from release_group_details() function since it's already done in get_release_group_by_id().
Added provider attribute for lyrics urls in release groups.
Not showing block with external links on release group page if there are no external links.
Updated structure of artist page. Added sidebar with additional info.
+ Other small tweaks.
Added sorting in Release Group-URL relationship processor.
Fixed styling of reviewed release groups on artist page.
Adjusted number of items on artist page.
Made release groups look better on small devices.
Updated icon for external URLs without an icon.
Fixed incorrect cache key generation in browse_release_groups().
Removed redundant info from artist page (release type in each thumbnail).
Added support for mbspotify mapper.
Added Spotify embed on release group page.
Added support for external links to Twitter and YouTube.
Renamed variables in relationship processor for release groups.
Replacing cover art with Spotify embed if link is known.
Set white theme on Spotify embed.
Adjusted style of left panel on release group page.
Fixed width of the left panel on extra small devices.
Fixed overlapping with Spotify embed on release group page.
Added max-width attribute to left panel on release group page to fix scrolling issues.