[scorecards] change question score to float

allows for negative points having decimal points, and prevents rounding
issues with some points being less than 0.5 and hence rounded to 0.

scoring/migrations/0017_alter_planquestionscore_score.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.21 on 2023-11-08 10:06
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('scoring', '0016_alter_planquestion_questiongroup'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='planquestionscore',
+            name='score',
+            field=models.FloatField(default=0),
+        ),
+    ]

scoring/models.py

@@ -557,7 +557,7 @@ class PlanQuestionScore(ScoreFilterMixin, models.Model):
         PlanQuestion, on_delete=models.CASCADE, related_name="questions"
     )
     answer = models.TextField(null=True, default="")
-    score = models.SmallIntegerField(default=0)
+    score = models.FloatField(default=0)
     max_score = models.PositiveSmallIntegerField(default=0)
     notes = models.TextField(null=True, default="")
     evidence_links = models.TextField(null=True, default="")