Add standard security workflows (#2)

These check for common security issues, as well as ensure that we
meet our license compliance obligations.

.github/workflows/codeql.yml

@@ -0,0 +1,40 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches:
+      - teleport
+  pull_request:
+    branches:
+      - teleport
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'python' ]
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v2
+      with:
+        languages: ${{ matrix.language }}
+
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v2
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v2
+      with:
+        category: "/language:${{matrix.language}}"

.github/workflows/dependency-review.yml

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+name: Dependency Review
+
+on:
+  pull_request:
+
+jobs:
+  dependency-review:
+    if: ${{ !startsWith(github.head_ref, 'dependabot/') }}
+    uses: gravitational/shared-workflows/.github/workflows/dependency-review.yaml@main
+    permissions:
+      contents: read