Nginx does not define a mime type for wav files by default. This causes Firefox to refuse to load these files.
Bu adding this mime type, we can ensure that Firefox plays back all interface sounds by default.
Issue is further described in: https://github.com/jitsi/jitsi-meet/issues/11860
Use 2 new environment variables to allow setting the number of nginx worker processes and connections. Add the variables to the docker-compose file and to the nginx-conf where default values are also set.
