feat: install supervisor from PyPI

This allows us to drop Python from the base image (reducing the size)
and use up to date supervisor version.

Author: nijel

requirements.txt

@@ -56,6 +56,7 @@ sentry-sdk==2.47.0
 siphashc==2.7
 social-auth-app-django==5.6.0
 social-auth-core==4.8.1
+supervisor==4.3.0
 tesserocr==2.9.1
 tomlkit==0.13.3
 translate-toolkit==3.16.3

start

@@ -321,7 +321,7 @@ set_real_ip_from 0.0.0.0/0;
     export WEB_RUNTIME_THREADS
 
     #  Execute supervisor
-    exec supervisord \
+    exec /app/venv/bin/supervisord \
         --loglevel="${SUPERVISOR_LOGLEVEL:-info}" \
         --logfile="${SUPERVISOR_LOGFILE:-/dev/null}" \
         --configuration=/etc/supervisor/supervisord.conf