[Multi-User Part 1]: Enable storage of settings for plaintext files based on user account (#498)

- Partition configuration for indexing local data based on user accounts
- Store indexed data in an underlying postgres db using the `pgvector` extension
- Add migrations for all relevant user data and embeddings generation. Very little performance optimization has been done for the lookup time
- Apply filters using SQL queries
- Start removing many server-level configuration settings
- Configure GitHub test actions to run during any PR. Update the test action to run in a containerized environment with a DB.
- Update the Docker image and docker-compose.yml to work with the new application design

src/database/migrations/0003_vector_extension.py

@@ -0,0 +1,10 @@
+from django.db import migrations
+from pgvector.django import VectorExtension
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("database", "0002_googleuser"),
+    ]
+
+    operations = [VectorExtension()]