NOOP: Format all layer's SQL code (#917)

I would like to reformat all of our SQL to have a concise coding style.
This makes it far easier to understand the code for a casual contributor,
and lets us spot errors more easily.

Most importantly, it makes it much easier to grep (search) the code because it is more likely to be in the same syntax

Some key changes:
* SQL keywords are always UPPERCASE, e.g. `SELECT WHEN AS END ...`
* types, variables, aliases, and field names (identifiers) are always lower case
* `LANGUAGE 'plpgsql'` is now `LANGUAGE plpgsql` (no quotes)
* a few minor spacing/semicolon cleanups

P.S. Per @TomPohys request, `TABLE` is spelled using upper case despite being a type for consistency with PG Docs. Same for `LANGUAGE SQL` vs `LANGUAGE plpgsql`.

layers/aerodrome_label/layer.sql

@@ -1,41 +1,42 @@
-
 -- etldoc: layer_aerodrome_label[shape=record fillcolor=lightpink, style="rounded,filled", label="layer_aerodrome_label | <z10_> z10+" ] ;
 
-CREATE OR REPLACE FUNCTION layer_aerodrome_label(
-    bbox geometry,
-    zoom_level integer,
-    pixel_width numeric)
-  RETURNS TABLE(
-    osm_id bigint,
-    geometry geometry,
-    name text,
-    name_en text,
-    name_de text,
-    tags hstore,
-    class text,
-    iata text,
-    icao text,
-    ele int,
-    ele_ft int) AS
+CREATE OR REPLACE FUNCTION layer_aerodrome_label(bbox geometry,
+                                                 zoom_level integer,
+                                                 pixel_width numeric)
+    RETURNS TABLE
+            (
+                osm_id   bigint,
+                geometry geometry,
+                name     text,
+                name_en  text,
+                name_de  text,
+                tags     hstore,
+                class    text,
+                iata     text,
+                icao     text,
+                ele      int,
+                ele_ft   int
+            )
+AS
 $$
-  -- etldoc: osm_aerodrome_label_point -> layer_aerodrome_label:z10_
-  SELECT
+SELECT
+    -- etldoc: osm_aerodrome_label_point -> layer_aerodrome_label:z10_
     osm_id,
     geometry,
     name,
-    COALESCE(NULLIF(name_en, ''), name) AS name_en,
-    COALESCE(NULLIF(name_de, ''), name, name_en) AS name_de,
+    COALESCE(NULLIF(name_en, ''), name)                                  AS name_en,
+    COALESCE(NULLIF(name_de, ''), name, name_en)                         AS name_de,
     tags,
     CASE
-      %%FIELD_MAPPING: class %%
-      ELSE 'other'
-    END AS class,
-    NULLIF(iata, '') AS iata,
-    NULLIF(icao, '') AS icao,
-    substring(ele from E'^(-?\\d+)(\\D|$)')::int AS ele,
-    round(substring(ele from E'^(-?\\d+)(\\D|$)')::int*3.2808399)::int AS ele_ft
-  FROM osm_aerodrome_label_point
-  WHERE geometry && bbox AND zoom_level >= 10;
-$$
-LANGUAGE SQL
-IMMUTABLE PARALLEL SAFE;
+        %%FIELD_MAPPING: class %%
+        ELSE 'other'
+        END                                                              AS class,
+    NULLIF(iata, '')                                                     AS iata,
+    NULLIF(icao, '')                                                     AS icao,
+    substring(ele FROM E'^(-?\\d+)(\\D|$)')::int                         AS ele,
+    round(substring(ele FROM E'^(-?\\d+)(\\D|$)')::int * 3.2808399)::int AS ele_ft
+FROM osm_aerodrome_label_point
+WHERE geometry && bbox
+  AND zoom_level >= 10;
+$$ LANGUAGE SQL IMMUTABLE
+                PARALLEL SAFE;