docs: reorganize GitHub directory structure and improve PR template (#413)

* docs: reorganize GitHub directory structure and improve PR template

- Move pull_request_template.md from .github/.github/ to .github/
- Change PR template heading from markdown level 2 to level 1
- Convert README.md reference in PR template to a markdown link

* chore: move pull request template to uppercase directory

Relocated pull_request_template.md from .github/ to .github/PULL_REQUEST_TEMPLATE/
to align with GitHub's recommended directory structure. No content changes.

* added

* chore: remove outdated pull request templates for bug fixes, documentation updates, and feature additions

* chore: remove outdated pull request template

* chore: replace old pull request template with a new structured version

* chore: add contributing guidelines for Dokploy Open Source Templates

* chore: update contributing guidelines and refine pull request template

- Changed validation step in contributing guidelines to use `node dedupe-and-sort-meta.js`.
- Simplified pull request template by removing unnecessary sections and improving checklist formatting.

---------

Co-authored-by: Mauricio Siu <47042324+Siumauricio@users.noreply.github.com>

.github/PULL_REQUEST_TEMPLATE/pull_request_template.md

@@ -0,0 +1,17 @@
+## What is this PR about?
+
+New PR of [Template Name]
+
+## Checklist
+
+Before submitting this PR, please make sure that:
+
+- [ ] I have read the suggestions in the README.md file https://github.com/Dokploy/templates?tab=readme-ov-file#general-suggestions-when-creating-a-template
+- [ ] I have tested the template in my instance, so the maintainers don't spend time trying to figure out what's wrong.
+- [ ] I have added tests that demonstrate that my correction works or that my new feature works.
+
+## Issues related (if applicable)
+
+Close automatically the related issues using the keywords: `closes #ISSUE_NUMBER`, `fixes #ISSUE_NUMBER`, `resolves #ISSUE_NUMBER`
+
+Example: `closes #123`