feat(map): config.get lookups from configurable roots

We avoid compatibility break with user pillars by looking up
configuration values using `config.get` in configurable roots.

We provide a new parameter `map_jinja:config_get_roots` in the formula
`parameters/defaults.yaml`to retrives values not only from
`tplroot=openssh` but from `sshd_config` and `ssh_config` too.

We need to update the `_mapdata` reference files to include the new
`map_jinja:config_get_roots`.

openssh/parameters/defaults.yaml

@@ -2,6 +2,12 @@
 # vim: ft=yaml
 ---
 values:
+  map_jinja:
+    config_get_roots:
+      - openssh
+      - sshd_config
+      - ssh_config
+
   openssh:
     sshd_enable: true
     sshd_binary: /usr/sbin/sshd