External CloudFlare resolver (#245)

Adding support for an external CloudFlare bypasser service and
introducing a new Docker image build with a dedicated target.

Key Changes
- Added `cloudflare_bypasser_external.py` for external bypasser
integration.
- Updated Docker Compose files to support the new service.
- Introduced a new Docker target for building a separate image for the
external bypasser.
- Refactored relevant modules to utilize the external bypasser when
configured.
- Documentation and configuration updates to reflect new options and
Docker targets.

Impact
- Users can now choose between internal and external CloudFlare
bypassing.
- New Docker image and target streamline deployment of the external
bypasser.
- Improved modularity and maintainability.
- No breaking changes for existing workflows.

Testing
- Manual and E2E tests performed for both bypasser modes.
- Docker Compose setups and new image build verified for development and
production.

Notes
Please review the new configuration options and Docker targets. Update
your environment and deployment scripts as needed. Feedback and
suggestions are welcome!

Dockerfile

@@ -38,18 +38,10 @@ RUN apt-get update && \
     curl \
     # For entrypoint
     dumb-init \
-    # For dumb display
-    xvfb \
-    # For screen recording
-    ffmpeg \
     # For debug
     zip iputils-ping \
     # For user switching
-    sudo \
-    # --- Chromium Browser ---
-    chromium-driver \
-    # For tkinter (pyautogui)
-    python3-tk && \
+    sudo && \
     # Cleanup APT cache *after* all installs in this layer
     apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false && \
     apt-get clean && \
@@ -67,17 +59,12 @@ WORKDIR /app
 
 # Install Python dependencies using pip
 # Upgrade pip first, then copy requirements and install
-# Copying requirements.txt separately leverages build cache
-COPY requirements.txt .
-RUN pip install --no-cache-dir -r requirements.txt && \
+# Copying requirements-base.txt separately leverages build cache
+COPY requirements-base.txt .
+RUN pip install --no-cache-dir -r requirements-base.txt && \
     # Clean root's pip cache
     rm -rf /root/.cache
 
-# Add this line to grant read/execute permissions to others
-RUN chmod -R o+rx /usr/bin/chromium && \
-    chmod -R o+rx /usr/bin/chromedriver && \
-    chmod -R o+w /usr/local/lib/python3.10/site-packages/seleniumbase/drivers/
-
 # Copy application code *after* dependencies are installed
 COPY . .
 
@@ -101,10 +88,34 @@ ENTRYPOINT ["/usr/bin/dumb-init", "--"]
 
 FROM base AS cwa-bd
 
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+    # For dumb display
+    xvfb \
+    # For screen recording
+    ffmpeg \
+    # --- Chromium ---
+    chromium \
+    # --- ChromeDriver ---
+    chromium-driver \
+    # For tkinter (pyautogui)
+    python3-tk
+
+# install additional dependencies
+COPY requirements-cwa-bd.txt .
+RUN pip install --no-cache-dir -r requirements-cwa-bd.txt && \
+    # Clean root's pip cache
+    rm -rf /root/.cache
+
+# Add this line to grant read/execute permissions to others
+RUN chmod -R o+rx /usr/bin/chromium && \
+    chmod -R o+rx /usr/bin/chromedriver && \
+    chmod -R o+w /usr/local/lib/python3.10/site-packages/seleniumbase/drivers/
+
 # Default command to run the application entrypoint script
 CMD ["/app/entrypoint.sh"]
 
-FROM base AS cwa-bd-tor
+FROM cwa-bd AS cwa-bd-tor
 
 ENV USING_TOR=true
 
@@ -124,3 +135,9 @@ RUN apt-get update && \
 
 # Override the default command to run Tor
 CMD ["/app/entrypoint.sh"]
+
+FROM base AS cwa-bd-extbp
+
+ENV USING_EXTERNAL_BYPASSER=true
+
+CMD ["/app/entrypoint.sh"]