Run application in web /context-path (for reverse-proxying)

Nobody has claimed this yet.

My request is to provide ability to run Matomo under a different /context-path than root.

Motivation is that we would like to *must* deploy several applications under the same `https` port on the load balancer, instead of dedicating a port to Matomo. My ITSM confirmed that they won't open anything but 443.

A lot of applications for Docker include the ability to deploy themselves under a different `/context-path` via properties.

I have not run yet Matomo as I am doing bill of materials at the moment. As Matomo will have to co-exist with other web applications on the same server, it would be preferrable to distinguish them by context path rather than port number.

Maybe this is already possible and my issue reduces itself to documenting that on the README.

Thank you for attention

Start by reviewing the Matomo Docker project and its README for existing context-path or reverse-proxy configuration. Check whether Matomo can already run below a non-root path; if not, identify the Docker configuration and documentation needed to support deployment under a shared HTTPS endpoint. Done means the setup works under a chosen /context-path and the supported configuration is documented.

Written by the indexing model from the issue text.