@Override
    public ConfigDefinition get(ConfigDefinitionKey key) { return configDefinitions.get(key); }
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