Another attempt at overlap query fix

It appears this is a problem on mysql because ST_Area()
bombs on non-2D objects while MariaDB just returns 0.

What we actually care about is ST_Contains() and not
ST_Intersects(). ST_Intersects() will return true if only an
edge intersects, but ST_Contains() will ensure there's
at least some amount of containment/area.

I've kept ST_Intersects() in front of ST_Contains() because
the query was super slow without it. Keeping it reduces calls to
ST_Contains().

db_store/sql/3_overlap_fix.up.sql

@@ -0,0 +1,24 @@
+-- Fix procedure for overlap disablement
+-- mysql (at least old 8.0.x)'s ST_Area throws an
+-- error on non-poly/mpoly (2D objects). (MariaDB's
+-- ST_Area will return 0 for non-poly/mpoly.)
+-- It looks like ST_Overlaps would work as a replacement
+-- for ST_Intersects which gives us what we want. However,
+-- that is very slow. Keeping the ST_Intersects in front
+-- of ST_Overlaps keeps it fast.
+DROP PROCEDURE IF EXISTS fl_nest_filter_overlap;
+CREATE PROCEDURE fl_nest_filter_overlap (IN maximum_overlap double)
+BEGIN
+  DROP TEMPORARY TABLE IF EXISTS overlapNest;
+  CREATE TEMPORARY TABLE overlapNest AS (
+    SELECT b.nest_id
+    FROM nests a, nests b
+    WHERE a.active = 1 AND b.active = 1 AND
+        a.m2 > b.m2 AND
+        ST_Intersects(a.polygon, b.polygon) AND
+        ST_Overlaps(a.polygon, b.polygon) AND
+        (100 * ST_Area(ST_Intersection(a.polygon,b.polygon)) / ST_Area(b.polygon)) > maximum_overlap
+  );
+  UPDATE nests a, overlapNest b SET a.active=0, discarded = 'overlap' WHERE a.nest_id=b.nest_id;
+  DROP TEMPORARY TABLE overlapNest;
+END