feat(core,meta,app,android,ios): title logos and runtimes

ani.zip sent each series' TVDB clear logo and every episode's running
time from the start, and neither was kept. Enrichment now stores the logo
in title_metadata.logo_url (kept across a refresh of the same entry, like
the fanart) and episode runtimes in episode_metadata.runtime, TVDB's
first and AniDB's length after it. AniList's duration lands in
TitleDetails::runtime; TMDB episode runtimes are kept too.

Schema v13 adds the two columns and marks AniList titles un-enriched
without deleting anything. TitleDetails::revision lets details written
before runtime existed refetch by id while the old ones stay on screen,
instead of blanking them in the migration as v10 did.

Clear logos are padded to a square, so each client crops them to their
visible pixels before drawing. The logo replaces the name on the
library's banner and the title page (not on a light theme's title page,
where lettering made for dark art can vanish). Episode rows show how long
they run, in place of the file size on Android and iOS; a film's runtime
joins its line of facts.

docs/USER_GUIDE.md

@@ -72,6 +72,9 @@ Click a title to open its page. **Esc** goes back.
 - Each episode shows a tick when you have watched it. Right-click an episode and choose **Mark
   watched up to here** to tick it and every episode before it.
 - **In this franchise** lists the other parts of the series, when posters and descriptions are on.
+- With posters and descriptions on, a show's logo takes the place of its name at the top of the
+  page and on the library's banner, and each episode says how long it runs. A film says how long
+  it runs in the line under its name.
 
 An episode counts as watched once you have seen 90% of it.