cuda.device_empty function

[smazouz42]

This pull request addresses issue #57 by adding a new feature to 'cuda' device_empty that allows you to allocate memory on the GPU

[pyccel-bot[bot]]

Hello again! Thank you for this new pull request :star_struck:.

Please begin by requesting your checklist using the command /bot checklist

[smazouz42]

Here is your checklist. Please tick items off when you have completed them or determined that they are not necessary for this pull request:

• [ ] Write a clear PR description
• [ ] Add tests to check your code works as expected
• [ ] Update documentation if necessary
• [ ] Update Changelog
• [ ] Ensure any relevant issues are linked
• [ ] Ensure new tests are passing