feat: support deep base URLs

[fgreinacher]

This MR adds support for passing deep base URLs like /foo/bar.

For Jetty I had to move away from the current convention based approach because that only support simple URLs with a single path element (see deployment rules). The best way to implement this in a generic way cases seems to be the config file approach. That also supports environment variables out of the box and therefore reduces complexity in the entrypoint script and in the Dockerfile.

For Tomcat it's a bit easier because it supports such URLs out of the box via special file name conventions, see https://tomcat.apache.org/tomcat-9.0-doc/config/context.html#Naming.

I made multiple manual tests to verify things are working as expected:

• ✅ docker build . -f Dockerfile.tomcat -t plantuml-server && docker run -p 8080:8080 -it -e BASE_URL=foo/ plantuml-server
• ✅ docker build . -f Dockerfile.tomcat -t plantuml-server && docker run -p 8080:8080 -it -e BASE_URL=foo/bar plantuml-server
• ✅ docker build . -f Dockerfile.tomcat -t plantuml-server && docker run -p 8080:8080 -it plantuml-server
• ✅ docker build . -f Dockerfile.tomcat -t plantuml-server && docker run -p 8080:8080 -it -e BASE_URL=/foo plantuml-server
• ✅ docker build . -f Dockerfile.jetty -t plantuml-server && docker run -p 8080:8080 -it -e BASE_URL=foo/ plantuml-server
• ✅ docker build . -f Dockerfile.jetty -t plantuml-server && docker run -p 8080:8080 -it -e BASE_URL=foo/bar plantuml-server
• ✅ docker build . -f Dockerfile.jetty -t plantuml-server && docker run -p 8080:8080 -it plantuml-server
• ✅ docker build . -f Dockerfile.jetty -t plantuml-server && docker run -p 8080:8080 -it -e BASE_URL=/foo plantuml-server

🛠 with ❤️ by Siemens

[fgreinacher]

Thanks a lot for the merge @arnaudroques - do you already know when the next release will happen?

[arnaudroques]

Thanks a lot for the merge @arnaudroques - do you already know when the next release will happen?

Probably next week, hoping everything will work fine :-)