Refactor template helpers

[rosle]

Why

Extract any helpers to separate modules or classes rather than putting them all in a template file.

Who Benefits?

Developers who work on the template

[rosle]

I started working a bit on https://github.com/nimblehq/rails-templates/pull/318/files

[rosle]

Please take this into account #317 (comment)

[rosle]

Please take care of These Rubocop todos for Style/ClassAndModuleChildren - https://github.com/nimblehq/rails-templates/pull/320/files#r828745952

[malparty]

@rosle I think @sanG-github will soon work on the prompt flow which should also refactor some of the helpers, should you two have a small call about sharing what was intended in this issue?

Then could you let me know if this issue should be closed or reviewed? 👀

Many thanks 🙏