5.0.0 Beta 8

#2918: Update HTMLPurifier to 4.18.0
#2898: Rewrite import and export of database templates and page wrappers
#2955: Fix issues with loading legacy widget classes. Again.
#2941: Fix an issue where download fileFeed widgets can show broken thumbnails
#2954: Fix issue where RecordFeed blocks did not find custom block templates
#2957: Fix subject of assignment email notifications
#2961: Fix issue where some login methods cause a TypeError in the Account Settings
#2963: Prevent caching of DatabaseNavigation widget
#2965: Fix issues with UINode extension
#2966: Improved the UI of the onboarding ACP section
#2962: Fixes an issue where forum feed template would throw an error if last poster was anonymous
#2956: Fix issue where "tags updated" message appears even if nothing was changed
#2482: Adjusted the UI of editor dropdown menus
#2940: Rework LazyLoad queue to better handle large tables
#2942: Fix PHP error in converter Login
#2944: Clean up Google Analytics settings form
#2947: Removed the carousel effect for profile widgets on mobiles
#2953: Fix issue with undefined IN_DEV constant
#2948: Adjusted the font-sizes of Tag pages
#2943: Make record cover photo editable only if the user can edit the record
#2934: Fixed Download thumbmails in Grid mode
#2925: Allow comment pagination to use the record per page setting as a fallback
#2926: Fix manual color input in firefox
 - Issue #2328: ACP - Change Primary Email Color
 - Issue #2474: [B2-SH][Pages][Fields] Fancy colorpicker
#2923: Fire onItemView event for items that don't implement ViewUpdates
#2933: Improved UI of ACP search results
#2927: Restore datastore directory
#2932: "Manage Followed Content" tab shows correct content when opened in a new tab
#2916: Scan for extension language strings in the dev center