Support subpath in base URL

[atommaki]

Is your feature request related to a problem? Please describe.
Currently Traduora assumes it is running on the root of a URL, however behind a proxy (eg: for https) you may want to run it on a different URL (sub path), what is currently not possible.
My webserver running on server.mycompany.com and I would like to redirect the incoming request to the https://server.mycompany.com/traduroa to my traduora server (running in docker in my case). I couldn't find a good way doing that.

Here is some with the same struggle, patching Traduroa to achive this: https://eder-chamale.medium.com/publishing-traduora-over-sub-path-and-a-reverse-proxy-b65941b8aa53

Describe the solution you'd like
Would be nice to have a a new variable where I could define the base URL path, like TR_URL_BASE_PATH. Similarly as the currently existing TR_VIRTUAL_HOST for the domain.

Describe alternatives you've considered
Currently I manually update the following files to adjust the URL:

webapp/src/environments/environment.prod.ts
webapp/src/index.html

But this is just a workaround, the worst part is it's a build time solution, so I still can't make it dynamic for my container.