add "indexer" job column to support indexer choice in the future

so far we only had "StreetIndex" and "PoiIndex" only, and which to
use was determined by the chosen layout and whether a POI file was
attached to the job

in the future there will be multiple different indexers to choose
from, e.g StreetIndex and HealthIndex, and which one to use needs
to be maintained as part of the rendering job data

www/maposmatic/migrations/0025_maprenderingjob_indexer.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.2.12 on 2022-08-21 15:45
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('maposmatic', '0024_maprenderingjob_queue'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='maprenderingjob',
+            name='indexer',
+            field=models.CharField(max_length=256, null=True),
+        ),
+        migrations.RunSQL("UPDATE maposmatic_maprenderingjob SET indexer = 'Street' WHERE layout LIKE '%index%'"),
+    ]

www/maposmatic/migrations/0026_maprenderingjob_indexer.py

@@ -0,0 +1,11 @@
+from django.db import migrations, models
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('maposmatic', '0025_maprenderingjob_indexer'),
+    ]
+
+    operations = [
+        migrations.RunSQL("UPDATE maposmatic_maprenderingjob j SET indexer = 'poi' FROM maposmatic_uploadfile_job uj, maposmatic_uploadfile u WHERE j.id = uj.maprenderingjob_id AND uj.uploadfile_id = u.id AND u.file_type = 'poi'"),
+    ]

www/maposmatic/models.py

@@ -85,6 +85,7 @@ class MapRenderingJob(models.Model):
     stylesheet = models.CharField(max_length=256)
     overlay = models.CharField(max_length=256, null=True, blank=True)
     layout = models.CharField(max_length=256)
+    indexer = models.CharField(max_length=256, null=True)
     paper_width_mm = models.IntegerField()
     paper_height_mm = models.IntegerField()
     bitmap_dpi = models.IntegerField(default=72)