Added CodeQL and Bandit security checks as GitHub Actions (#3625)

* Added CodeQL and Bandit security checks as GitHub Actions

* Nit fix on defusedxml.ElementTree

* Remove defusedxml as hard requirement

* Changed diffusedxml/xml importing

* Fix compilation

* Removed Bandit specific changes
Co-authored-by: Nikita Shulga <nikita.shulga@gmail.com>
Co-authored-by: Nicolas Hug <nicolashug@fb.com>
Co-authored-by: Francisco Massa <fvsmassa@gmail.com>

.github/workflows/bandit.yml

+# GitHub Actions Bandit Workflow
+
+name: Bandit
+
+on:
+  pull_request:
+    branches: [ master ]
+
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      # Task will fail if any high-severity issues are found
+      # Ignoring submodules
+      - name: Run Bandit Security Analysis
+        run: |
+              python -m pip install bandit
+              python -m bandit -r . -x ./third_party -lll

.github/workflows/codeql.yml

+# GitHub Actions CodeQL Workflow
+
+name: CodeQL
+
+on:
+  pull_request:
+    branches: [ master ]
+
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v1
+        with:
+          languages: python, cpp
+
+      - name: Install Ninja
+        run: |
+              sudo apt-get update -y
+              sudo apt-get install -y ninja-build
+
+      - name: Update submodules
+        run: git submodule update --init --recursive
+
+      - name: Install Torch
+        run: |
+              python -m pip install cmake
+              python -m pip install torch==1.8.1+cpu -f https://download.pytorch.org/whl/torch_stable.html
+              sudo ln -s /usr/bin/ninja /usr/bin/ninja-build
+
+      - name: Build TorchVision
+        run: python setup.py develop --user
+
+      # If any code scanning alerts are found, they will be under Security -> CodeQL
+      # Link: https://github.com/pytorch/vision/security/code-scanning
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v1