Add convenience script to run the integrity test locally (#1495)

This PR adds a script that allows a developer to run the "integrity" CI script without actually creating a PR.

integrity.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+# A script to run the "integrity" continuous integration script.
+
+area=monaco
+echo MIN_ZOOM=0 >> .env
+echo MAX_ZOOM=14 >> .env
+./quickstart.sh $area
+export TEST_MODE=yes
+make generate-devdoc
+area=europe/monaco
+echo DIFF_MODE=true >> .env
+
+# Cleanup
+rm -fr data build cache
+# Create data/$area.repl.json
+make download-geofabrik area=$area
+# Download 2+ month old data
+export old_date=$(date --date="$(date +%Y-%m-15) -2 month" +'%y%m01')
+echo Downloading $old_date extract of $area
+docker-compose run --rm --user=$(id -u):$(id -g) openmaptiles-tools sh -c "wget -O data/$area.osm.pbf http://download.geofabrik.de/$area-$old_date.osm.pbf"
+# Initial import and tile generation
+./quickstart.sh $area
+sleep 2
+echo Downloading updates
+# Loop to recover from potential "ERROR 429: Too Many Requests"
+docker-compose run --rm --user=$(id -u):$(id -g) openmaptiles-tools sh -c "
+while ! osmupdate --keep-tempfiles --base-url=$(sed -n 's/ *\"replication_url\": //p' data/$area.repl.json) data/$area.osm.pbf data/changes.osc.gz ; do 
+  sleep 2;
+  echo Sleeping...;
+  sleep 630;
+done"
+echo Downloading updates completed
+echo Importing updates
+make import-diff
+echo Generating new tiles
+make generate-tiles-pg