Add rhdh-templates skill

[04kash]

Fixes: https://redhat.atlassian.net/browse/RHDHPLAN-1072

Summary

Adds a new rhdh-templates skill for authoring and validating Software Templates in RHDH which was made using the skill-maker skill

I tried creating a template from an existing repo (https://github.com/quarkusio/quarkus-quickstarts/tree/main/getting-started) as well as a small template from scratch and they ran without issues when I tried them locally. More details on the prompts I used alongside the skill to create these templates are here.

[karthikjeeyar]

Created a template using this skill and it worked successfully 🎉

---

I have a couple of observations :

1. Nunjuck syntax substitution in catalog.info.yaml isn't working as expected, I had to fix {{ values.* }} → ${{ values.* }} in the catalog.infor.yaml, There are few instance in skeleton examples and documentation that needs an update.

   Refer this repo for the right syntax - https://github.com/redhat-developer/red-hat-developer-hub-software-templates/blob/main/templates/create-backend-plugin/skeleton/plugins/%24%7B%7Bvalues.plugin_id%7D%7D-backend/catalog-info.yaml

2. Add a gotcha rule in gotchas-rules.json to detect {{ values. without $ prefix in skeleton files.

[karthikjeeyar]

/approve
/lgtm

[openshift-ci]

New changes are detected. LGTM label has been removed.