feat: add new fft algorithm

[ikocs]

Description of change A new direct and inverse fast Fourier transform algorithm has been added. The new algorithm uses templates. During development,

Checklist

• Added description of change
• Added filename conforms to filename guidelines
• Added tests and example, test must pass
• Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• Relevant documentation/comments are changed or added
• PR title follows semantic commit guidelines
• Search previous commits before making a new one, as yours may be a duplicate
• I acknowledge that all my contributions are made under the project's licence.

Notes: I also discovered that the old algorithm did not work correctly, and the test data was entered incorrectly. An independent check can be carried out using an online calculator.

I suggest replacing the old files with new ones, but have not yet removed them from the repository.

[github-actions]

This pull request has been automatically marked as abandoned because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions]

Please ping one of the maintainers once you commit the changes requested or make improvements on the code. If this is not the case and you need some help, feel free to ask for help in our Gitter channel or our Discord server. Thank you for your contributions!

[ikocs]

@Panquesito7 @realstealthninja Good afternoon, please conduct a review
thx