Fix render of PATCH_CONTENT in full_json_patch krm function

This will fix Helm inline values patch rendering

When using inline values such as:

```
inline_values:
  service:
    ports:
      http: "8080"
      https: "8443"
```

The current `full_json_patch()` function was failing with error: `Error:
bad expression, please check expression syntax`. This is because yq
seems like doesn't properly handle literal new-lines inside a
double-quoted string.

This change replace current implementation to a safer approach using
HEREDOCS template to render the patch.

Change-Id: If7e78a6509ca0e6731f3125eeb535cedf394b06b
Signed-off-by: mesaj <juanmanuel.mesamendez.ext@telefonica.com>
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/docker/osm-krm-functions/scripts/library/helper-functions.rc b/docker/osm-krm-functions/scripts/library/helper-functions.rc
index be3601a..d012b80 100644
--- a/docker/osm-krm-functions/scripts/library/helper-functions.rc
+++ b/docker/osm-krm-functions/scripts/library/helper-functions.rc
@@ -423,9 +423,10 @@
   done
 
   # Wrap a full patch around, adding target specification
+  export PATCH_CONTENT
   local PATCH_FULL=$(
     yq --null-input ".target.kind = \"${TARGET_KIND}\", .target.name = \"${TARGET_NAME}\"" | \
-    yq ".patch = \"${PATCH_CONTENT}\"" | \
+    yq ".patch = env(PATCH_CONTENT)" | \
     yq "[ . ]"
   )