fix(tours): keep the shipped ski migrations and follow the ski tour through

The winter label and four-discipline migrations are already on
feat/tours-board-rest, so a database that ran them would refuse to boot
or fail the old CHECK. 045500, 045520 and 046100 are back as they
shipped, and a new migration drops both winter_activity columns and
adds ski_discipline again with the six disciplines. The entity and
table types follow the column to its new place.

German, Hungarian, Indonesian and English no longer name the whole type
with the ski touring word, and the info dot speaks of ski tours and
tracks. search_tour_pois and its wiki row list rides and ski and winter
tours. Snowshoeing gets a snowshoe glyph instead of the walk's
footprints, a ski import without a discipline can be planned over (the
planner asks for it), and an overlay shown by default tries its tiles
afresh each time it comes on.

server/src/middleware/globalMiddleware.ts

@@ -326,7 +326,7 @@ export function applyGlobalMiddleware(
             // through fetch and needs it here.
             'https://tiles.openseamap.org',
             // OpenSnowMap's transparent piste layer (SKI-01), offered in the Tours planner with
-            // no tour open, for a hike and for a ski track; the GL map reads it through fetch.
+            // no tour open and for a ski tour; the GL map reads it through fetch.
             'https://tiles.opensnowmap.org',
             // OpenHikingMap, the hiking base map of the Tours planner (MAP-01), loaded only
             // while a user shows it and the admin allows it; GL reads it through fetch.