MONGO_PORT and render-db.properties port not working

[fcollman]

The docker packaging and the configuration file advertise a port can be set, but that isn't actually getting read by the mongo configuration code, which makes it fall back to the default port.

We should likely remove the MONGO_PORT option from the docker packaging and the configuration file, or fix the code to allow it to work. It seems like its looking for host:port in the servers line of the file.

https://github.com/saalfeldlab/render/blame/d65fb27ce59b7100293c360ba902e6a9ec443ee6/render-ws/src/main/java/org/janelia/render/service/dao/DbConfig.java#L142

[trautmane]

I think removal makes sense. Actually, I'd like to remove all of the individual connection parameters and simply support the MONGO_CONNECTION_STRING since that should cover everything now and in the future. One downside is it complicates scripting (and maybe Ansible?) since the connection string can contain ampersands and other script unfriendly characters. Would you be opposed to removal of all the individual connection parameters? (note: we only use the connection string at Janelia)