chore: remove Solari screen type and "v1" code

* Remove the `solari` screen type; we have no remaining screens of this
  type in the wild.

* Remove the "v1" screen page/API endpoints; there are now no remaining
  v1 screen types.

* Remove a substantial amount of code that was only used by v1 screens
  (likely not all of it, but there are few reliable tools available for
  detecting unused "public" code in Elixir).

* Remove the `solari_large_v2` screen type; this was added a long time
  ago in anticipation of the "large" Solari layout being ported to the
  v2 framework, but no real functionality was ever added to it, and the
  only screens of this type in the wild are now permanently offline and
  waiting to be decommissioned.

assets/css/pre_fare_v2.scss

@@ -2,11 +2,9 @@
 
 @import "colors";
 
-// Don't import from solari... put in common place!
 @import "fonts";
-@import "solari/arrow";
-@import "solari/departure_time";
 
+@import "v2/arrow";
 @import "v2/clock_icon";
 
 @import "v2/pre_fare/viewport";
@@ -36,6 +34,7 @@
 @import "v2/pre_fare/evergreen/video";
 
 @import "v2/placeholder";
+@import "v2/pre_fare/departure_time";
 @import "v2/pre_fare/elevator_status";
 @import "v2/pre_fare/flex/paging_indicator";
 @import "v2/pre_fare/full_line_map";