docs: add a PR template

[mkbreuningIOHK]

This PR is to add this PR template which is used as below:

Description:

Update the PR template to the one that was agreed by the IO tribe and that will be applicable to all related repositories, this one included.

Checklist:

• My PR follows the contribution guidelines of this project
• My PR is free of third-party dependencies that don't comply with the Allowlist
• [] I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• [] I have added tests that prove my fix is effective or that my feature works
• I have checked the PR title to follow the conventional commit specification

[github-actions]

Integration Test Results

 5 files  ±0   5 suites  ±0   11s ⏱️ ±0s
17 tests ±0  17 ✅ ±0  0 💤 ±0  0 ❌ ±0 
20 runs  ±0  20 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 0fde4d5. ± Comparison against base commit 99199f6.

[FabioPinheiro]

I don't want to start this question about the template again.

Checklist almost everything on the checklist could be just text for a new user to read and delete in the template.

[mkbreuningIOHK]

Let's follow-up on the contribution guideline link to add.

[petevielhaber]

• Minor change recommended