feat(instance): an instance says where it keeps people's data

Its operator sets DATA_LOCATION and BACKUP_LOCATION in deploy/.env (a
country's code or EU, the backups also none), and instance.info() hands
them on. The first start's tile and Switch account show the flag of
where the data is and the words, as labels ("Data: European Union",
"Backups: Switzerland"), the countries by the world map's CLDR names:
where the disks are, never which law governs. The flags come from the
flag package, which draws flag-icons; its MIT notice joins the licence
list.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

deploy/.env.example

@@ -81,6 +81,13 @@ SOURCE_URL=
 # Jellyfin server answers there; `none`: no suggestion.
 JELLYFIN_URL=
 
+# Where this instance keeps people's data, and its backups, which the app shows as a flag
+# and in words when someone chooses an instance: a country's code (ISO 3166-1 alpha-2,
+# `CH`) or `EU`; for the backups also `none`. Where the disks are, not which law governs
+# you as the operator: claim only that. Empty: the app says nothing.
+DATA_LOCATION=
+BACKUP_LOCATION=
+
 # How much room people's images and sounds may take on this instance, in MiB. Empty: the
 # defaults, 100 for an anonymous person (anonymous accounts are meant to become identified
 # ones), 500 for one signed in with GitHub, and 15000 for everyone together (0: no limit