private void initialize(File definitionDir) {
        if ( ! definitionDir.exists()) return;

        for (File def : definitionDir.listFiles((dir, name) -> name.matches(".*\\.def")))
            addConfigDefinition(def);
    }
A global pool of all config definitions that this server knows about. These objects can be shared
by all tenants, as they are not modified.

@author Ulf Lilleengen
config-application-package/src/main/java/com/yahoo/config/model/application/provider/StaticConfigDefinitionRepo.java