feat(maj.jinja): authorise literal file path in “map.jinja:sources”

This mimic the behavior of “libtofs.jinja”.

TEMPLATE/map.jinja

@@ -34,7 +34,17 @@
 
 {%- for map_source in map_sources %}
   {# Lookup the grain/pillar/... #}
+  {# Fallback to use the source name as a direct filename #}
   {%- set map_values = salt['config.get'](map_source, []) %}
+
+  {# Mangle `map_source` to use it as literal path #}
+  {%- if map_values|length == 0 %}
+    {%- set map_source_parts = map_source.split('/') %}
+    {%- set map_source = map_source_parts[0:-1] | join('/') %}
+    {%- set map_values = map_source_parts[-1].rstrip('.yaml') %}
+  {%- endif %}
+
+  {# Some configuration return list #}
   {%- if map_values is string %}
     {%- set map_values = [map_values] %}
   {%- endif %}

TEMPLATE/parameters/defaults.yaml

@@ -12,11 +12,17 @@ subcomponent:
 # Just here for testing
 added_in_defaults: defaults_value
 winner: defaults
-# Configure map.jinja to load formula parameters values
+# Configure map.jinja to load formula parameters values and merge them
+# in the order from most generic (first) to most specific (last).
+# Each source can define the merging `strategy` which default to the
+# `smart` strategy of `salt.slsutil.merge`.
+# Note: Any value not evaluated by `config.get` will be used literally.
+# This can be used to set custom paths, as many levels deep as required.
 map.jinja:
   sources:
     - osarch
     - os_family
     - os
     - osfinger
     - roles
+    - any/path/can/be/used/here.yaml