feat: support deep base URLs

docker-entrypoint.tomcat.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+# cspell:words mkdir
+# cspell:enableCompoundWords
+###########################################################
+
+# choose war file name so that context path is correctly set based on BASE_URL,
+# following the rules from https://tomcat.apache.org/tomcat-9.0-doc/config/context.html#Naming,
+# specifically remove leading and trailing slashes and replace the remaining ones by hashes.
+export FILE_NAME="$(echo "$BASE_URL" | sed -e 's:^/::' -e 's:/$::' -e 's:/:#:g')"
+export FILE_PATH="$WEBAPP_PATH/$FILE_NAME.war"
+mv /plantuml.war "$FILE_PATH"
+
+# base image entrypoint
+if [ -x /docker-entrypoint.sh ]; then
+    /docker-entrypoint.sh "$@"
+else
+    exec "$@"
+fi