Create org-wide PR template

[pombredanne]

Short Description

We need to better communicate that we may not want to spend too much on vibe coded PRs, PRs missing tests and so on

Possible Solution/Implementation Details

Let's create an org-wide PR template and updated guidelines like in https://github.com/aboutcode-org/scancode-toolkit/blob/develop/CONTRIBUTING.rst and https://github.com/aboutcode-org/scancode-toolkit/blob/develop/.github/PULL_REQUEST_TEMPLATE.md to make it clear when PR were vibe coded.

[pombredanne]

See https://github.com/aboutcode-org/.github