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* chore: remove outdated pull request templates for bug fixes, documentation updates, and feature additions

* chore: remove outdated pull request template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

@@ -14,4 +14,4 @@ Before submitting this PR, please make sure that:
 
 Close automatically the related issues using the keywords: `closes #ISSUE_NUMBER`, `fixes #ISSUE_NUMBER`, `resolves #ISSUE_NUMBER`
 
-Example: `closes #123`
+Example: `closes #123`