Add background task to export suspicious IPs to text file

- Implement export-malicious-ips task that queries distinct IPs flagged
    as is_suspicious from database and writes to exports/malicious_ips.txt
  - Add exports volume mount to docker-compose.yaml for host persistence
  - Update entrypoint.sh to fix ownership of exports directory for krawl user
  - Update Dockerfile to create /app/exports directory during build

Other tasks can be added by creating them in the tasks dir using the same setup as this task.
All tasks *MUST* include a TASK_CONFIG dict and a main method in the file to work correctly.

Dockerfile

@@ -16,7 +16,7 @@ COPY wordlists.json /app/
 COPY entrypoint.sh /app/
 
 RUN useradd -m -u 1000 krawl && \
-    mkdir -p /app/logs /app/data && \
+    mkdir -p /app/logs /app/data /app/exports && \
     chown -R krawl:krawl /app && \
     chmod +x /app/entrypoint.sh