Merge pull request #787 from thezoggy/dev--redirect_fixes

Redirect fixes and pep8 related corrections.
Remove legacy Metadata conversion (pre-ini migration). Due to db min version checking, this can be safely dropped as it is 3+ years old.
Correct layout style for metadata options in the UI. The slight incorrect offset became noticeable with more options being added.
renamed: season_thumbnails -> season_posters
added initial support to do: season_posters, season_banners, season_all_images (default)
 -- wired it up so they all key off season_posters for the moment (so I wouldn't have to code up the migration/backend just yet).
added initial support to do: banner
 -- wired it up so it keys off poster for the moment (so I wouldn't have to code up the migration/backend just yet).
slight reordering to match ui
Remove Synology metadata - was a clone of MB and does not appear to actually be used by synology units.
split show_all_images into -> show_all_poster / show_all_banner
Change initializing and saving metadata
wording update