Handle additional conditions for resolving variables

[cherylking]

In ServerConfigDocument, there is logic that resolves variables referenced by server.xml for the application location and name. This logic processes all the config files that Liberty looks in, but does not look at system properties or environment variables. The document here (https://openliberty.io/docs/ref/config/) indicates those should be used. In a build environment, perhaps that does not make sense. But we should look into it and ensure this behavior is intentional.

That document also covers additional syntax for resolving variable references that we are not handling. We should add logic for this. Here is an excerpt:

Replace all non-alpha num characters with _

Change all characters to upper case.

If you enter ${my.env.var} in server.xml it will look for environment variables with the following names:

my.env.var

my_env_var

MY_ENV_VAR

[cherylking]

This part of the Liberty doc is also new since this code was last updated. Need to handle this as well.