Improve placement of model in curve3D render tab

[sayomaki]

Description

This PR fixes #218 where the space usage of the model in the curve3D render output tab is not very optimised. I have shifted the design to a more top-bottom style (instead of the current left-right arrangement).

The changes have been tested and checked locally (see screenshot below):

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Changes have been tested locally, and all tests and lints passed with no additional warnings/errors introduced by the PR.

Checklist:

(Note: Some of the items are not applicable for this PR)

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[RichDom2185]

LGTM, thanks a lot!