Add test format versioning to storage benchmarks

Adds a test_format database column and a value in the API return for the
test format version, starting at 0 for the existing format as of 0.9.37.

References #143

api-daemon/migrations/versions/5c2109dbbeae_pvc_version_0_9_37.py

@@ -0,0 +1,28 @@
+"""PVC version 0.9.37
+
+Revision ID: 5c2109dbbeae
+Revises: bae4d5a77c74
+Create Date: 2021-10-02 00:47:29.693579
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '5c2109dbbeae'
+down_revision = 'bae4d5a77c74'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('storage_benchmarks', sa.Column('test_format', sa.Integer(), server_default='0', nullable=False))
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('storage_benchmarks', 'test_format')
+    # ### end Alembic commands ###