Allow providing a custom database port when setting up Matomo (through installation form and env variable)

[frapell]

Summary

I am trying to install matomo using the official docker image, using a hosted mysql database with a custom port (ie. not 3306), and I am unable to connect to it, mainly because there is no way to provide the port to connect to...

I saw this PR #13676 which includes a bunch of env vars, but no MATOMO_DATABASE_DBPORT or similar. I tried using host:port with the MATOMO_DATABASE_HOST variable, but that doesn't work.

I also found this matomo-org/docker#172 from 2019, but I guess it is not a desired feature to have?

Is there a quick workaround I could try?

[sgiehl]

@frapell you could maybe use the https://github.com/matomo-org/plugin-EnvironmentVariables plugin, which should allow to provide additional configs as env variables.

Besides that I don't have an idea. The problem is, that even the default Matomo installation process currently does not allow to provide a custom database port, but always assumes the default port. So this would be something we need to change aswell.