Issue #56, Start addressing issue #40 (document, permissions, sources, tags and user_management apps)
Issue #56, Remove per source icon support
Issue #56, Remove the MAIN_VERBOSE_LOGIN configuration option
Issue #56, Remove the MAIN_THEME configuration option
Remove insertion of the web_theme value into the templates
Issue #56, Remove specialized Sentry link
Issue #56, Remove the MAIN_DISABLE_ICONS setting configuration option
Merge branch 'feature/remove_source_icons' into development