Add information about software design page

[aysunrhn]

I added a new section about software design, the information is at a high level and focuses on research software. It includes:

• Practical guide to designing software architecture
• C4 approach to software design
• Additional resources (videos and etc.) and further reading

Closes #233

[edvinskis]

Many thanks for this high-quality PR! I made a few minor revisions (updated categories, reworded introductory and some other sentences, fixed a typo, and standardized callout formatting).

I'll merge it now!

[Copilot]

Pull Request Overview

This PR adds a comprehensive software design guide focused on research software development. It introduces a new documentation section covering practical approaches to software architecture design, emphasizing principles specific to research contexts like reproducibility, transparency, and scientific collaboration.

Key changes include:

• Created a complete software design guide with step-by-step implementation approach
• Integrated the C4 modeling framework for documenting software architecture at multiple levels
• Added extensive resources and references for further learning

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
docs/software/development_workflow/software_design.qmd	New comprehensive guide covering software design principles, step-by-step implementation, and C4 modeling approach
docs/software/development_workflow/index.md	Added feature section linking to the new software design guide
_quarto.yml	Updated navigation to include the new software design page in the development workflow section

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