Converted examples to functional. Made compute_backend name consistent.

[mehdiataei]

Contributing Guidelines

• I have read and understood the CONTRIBUTING.md guidelines

Description

• Converted examples to functional (except lid-driven cavity, as it has a distributed version that inherits from it)
• Made compute_backend name consistent

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)
• Documentation update

How Has This Been Tested?

• All pytest tests pass

Linting and Code Formatting

Make sure the code follows the project's linting and formatting standards. This project uses Ruff for linting.

To run Ruff, execute the following command from the root of the repository:

ruff check .

• Ruff passes

[hsalehipour]

Please move all function defintion in the examples to the top of the file. Then start all the scripts one after another. Right now, functions and scripts are mixed up together.

[mehdiataei]

That is not always possible since we use those calls and values in the following functions. Because this is a script rather than reusable functions, it is completely acceptable to not pass those parameters and instead just use them inside the function.

[mehdiataei]

It IS a bad practice (and a linting error) to assume those values will be available in "future" calls. Codes must be well defined if read from top.

[hsalehipour]

please run ruff format . before merge. Otherwise this PR looks good to me.

[hsalehipour]

This PR addressed issue #103