[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

.github/workflows/pre-commit.yml

@@ -0,0 +1,48 @@
+name: pre-commit
+
+on:
+  pull_request:
+    paths:
+      - src/**
+      - tests/**
+      - config/**
+      - pyproject.toml
+      - .pre-commit-config.yml
+      - .github/workflows/test.yml
+  push:
+    branches:
+      - master
+    paths:
+      - src/khoj/**
+      - tests/**
+      - config/**
+      - pyproject.toml
+      - .pre-commit-config.yml
+      - .github/workflows/test.yml
+
+jobs:
+  test:
+    name: Run Tests
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.11
+
+      - name: ⏬️ Install Dependencies
+        run: |
+          sudo apt update && sudo apt install -y libegl1
+          python -m pip install --upgrade pip
+
+      - name: ⬇️ Install Application
+        run: pip install --upgrade .[dev]
+
+      - name: 🌡️ Validate Application
+        run: pre-commit run --hook-stage manual --all