feat: adds dynamic group positioning

[Eein]

This PR adds:

• a dynamic grouping toggle and offset slider to the group element. It will check for the Dynamic bool and render its children in accordance to its index and the proposed offset. This is a similar feel to how weakauras achieves this.
• a cheeky line of code to allow development on Linux

This also should be backwards compatible, but testing may be required.

Note: Developing on Linux and so I don't have access to linting/tools in Visual Studio. Let me know if there are style changes required. I'm also not a C# developer, so criticism expected!

[Eein]

~Fixing one more thing and i'll rerequest review~

Everything looks good on my end. Testing now.

Edit: Testing looks good

[Tischel]

Implemented in https://github.com/DelvUI/DelvCD/pull/31