Return the base URL of this module on the server. (e.g.
"https://localhost:8080/myProject")
This method may return null if this server does not have a valid configuration
or if the server is not running. The returned URL must not end in a trailing
slash.
If the module is null, the returned URL will just be to the root of
the server (e.g. "https://localhost:8080")
If the module is not already added to the server, the method will return
as close an approximation as possible. (for instance, for a J2EE web project
it may use the project's context root, which may not be the same when deployed
to a server)
