Fix location of hostdirs for Murano services

Use "{{ node_config_directory }}/murano-api/" for `murano-api` and
"{{ node_config_directory }}/murano-engine/" for `murano-engine`, so
correct `config.json` are mounted in containers.

Change-Id: I824ff00f6b86aac3eab5dc6fd01728653b4661d1
Closes-Bug: 1811716