treewide: improve template expansion

also: support *.toml as extra configuration dictionaries

Dockerfile

@@ -20,7 +20,7 @@ RUN python3 -m compileall -q -j 2 /usr/local/lib/j2cfg/
 RUN libpython="${PYTHON_SITE_PACKAGES%/*}" ; \
     find "${libpython}/" -mindepth 1 -maxdepth 1 -printf '%P\0' \
     | sed -zEn \
-      -e '/^(collections|concurrent|encodings|importlib|json|logging|multiprocessing|re|urllib)$/p' \
+      -e '/^(collections|concurrent|encodings|importlib|json|logging|multiprocessing|re|tomllib|urllib)$/p' \
     | sort -zV \
     | env -C "${libpython}" xargs -0r \
       python3 -m compileall -q -j 2 ; \
@@ -33,9 +33,7 @@ RUN libpython="${PYTHON_SITE_PACKAGES%/*}" ; \
       python3 -m compileall -q -j 2
 
 ## Python cache warmup
-RUN j2cfg-single /usr/local/lib/j2cfg/j2cfg/test.j2 /tmp/test ; \
-    cat /tmp/test ; echo ; echo ; \
-    rm -f /tmp/test
+RUN env -C /usr/local/lib/j2cfg/j2cfg j2cfg-single test.j2 -
 
 WORKDIR /pycache
 RUN find /usr/local/ -type f -name '*.py[co]' -printf '%P\0' \