ZH-349 - Add GitHub introduction for maintainers

[M-casado]

Summary

Added a new GitHub introduction guide for maintainers, to onboard quickly on the bare minimum features that the role would need.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New content (non-breaking change which adds new content)
• Modified content (non-breaking change which modifies existing content)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Motivation and Context

During the onboarding of T4.3 and also during the review of D4.2, it was mentioned that some node maintainers may not be familiar with GitHub. This motivated the creation of this introductory document.

References

ZenHub #349

Changes Introduced

• Added GitHub introductory guide for maintainers
• Added supplementary images

Review

NA

Checklist:

General Compliance:

• My changes follow the code style of this project (GDI SOP Style Guide) and the file naming conventions of the file accessioning proposal.
• I have verified that all new updated content is accessible, including checking that all external references are readable (i.e., no broken links). These may include references to external resources that should be resolvable, and internal references among SOPs.
• I have properly added this PR's changes to the repository CHANGELOG.md.

Only applicable if the PR includes new, or changes to, GDI SOPs (i.e., documents at sops/):

• My SOP-related changes adhere to the Generic SOP Template, including format and required fields.
• I have consulted the Charter, ISM, and ORR documents to ensure compliance.
• I am complying with the established procedure for SOP creations and modifications, including respecting review phases and notifying needed contributors for reviews.

[M-casado]

Just as a note: one of the GitHub actions (the one that compares the SOP index table) is failing but as intended, since the target branch is main and not dev, hence why there are no SOPs yet and it complains.

[dav-salgado]

Ok with me

[dav-salgado]

Perfect great job @M-casado

[elisavettorstensson]

I think the document is very informative, and I really like how well you’ve combined text and screenshots to make the procedures easier to understand! I have some experience with GitHub, and it feels like you’ve highlighted the most important points to consider when working with it. I left a comment about a section that I think might be difficult to understand. There are a few links that don’t lead to a page, but I assume you’re already aware of them and plan to update those. In a few places, you might add some commas for clarity, but that’s a minor detail. You've done a fantastic job as always—bravo!

[M-casado]

Reviewed during the introduction session I gave with Gabi, Bianca, Mattias and Elisavet.