i18n: make localization context non-global

- Simplify Localization{Context,Manager} to just Localization
- Fixed a bunch of lifetime issueo
- Removed all Arcs and Locks
- Removed globals
  * widgets now need access to &mut Localization for i18n

Signed-off-by: William Casarin <jb55@jb55.com>

Cargo.toml

@@ -65,7 +65,7 @@ tracing = { version = "0.1.40", features = ["log"] }
 tracing-appender = "0.2.3"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 tempfile = "3.13.0"
-unic-langid = "0.9.6"
+unic-langid = { version = "0.9.6", features = ["macros"] }
 url = "2.5.2"
 urlencoding = "2.1.3"
 uuid = { version = "1.10.0", features = ["v4"] }