Adding new diagram type - Block Diagram

[knsv]

📑 Summary

This PR introduces comprehensive support for Block Diagrams in Mermaid, offering users a versatile and intuitive way to represent complex systems, processes, or architectures visually. The new feature enhances the existing Mermaid suite by allowing for full control over the positioning of shapes, making it ideal for creating clear and concise block diagrams.

Resolves #3358

Example

Code:

```mermaid
block-beta
    columns 3
    %% whitespace has been added to make the code easier to read
    space             a(("🚀"))               space
                       space:3
                      c("🌝"):3
    d1<[" "]>(down) d2<[" "]>(down) d3<[" "]>(down)

    block:e1:3
        sube1(("👽")) sube2(("👾"))   sube3(("🛸"))
    end

    d4<[" "]>(down)                         space:2
    g("🤯")         r1<[" "]>(right)      f(("👯‍♂️"))

    a --> c
```

📏 Design Decisions

The implementation of Block Diagrams in Mermaid focuses on user flexibility and ease of use. Key features include:

• Customizable Block Positioning: Unlike the automatic layout in flowcharts, block diagrams allow users to precisely control the placement of shapes, ensuring diagrams meet specific layout requirements.
• Variety of Shapes and Styles: A range of block shapes, from standard rectangles to specialized forms like cylinders and parallelograms, enables diverse representations of different elements. Additionally, extensive styling options for individual blocks allow for visually distinctive diagrams.
• Advanced Linking Capabilities: Various arrow types and the ability to include text on links provide nuanced ways to represent relationships and flows between components.
• Dynamic Column Widths: Blocks automatically adjust their sizes based on content, ensuring a balanced and readable layout.

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added necessary unit/e2e tests.
• 📓 have added documentation. Make sure MERMAID_RELEASE_VERSION is used for all new features.
• 🔖 targeted develop branch

[aloisklink]

Just delete the packages/mermaid/src/docs/syntax/block-old.md file (see #5221 (comment)), then this looks good to me to merge :)

Thanks for going through all those comments, I imagine it must have been a pain to fix everything. 🚀