Feature: confirm request command before running request

[boltlessengineer]

Issues

• I have checked existing issues and there are no existing ones with the same request.

Feature description

related: #435

Having ability to view / edit the request command before running would be nice feature to have.
We can use :confirm command modifier instead of introducing flags to :Rest run arguments.

So running :confirm Rest run will print the cli command to run and ask users to edit the command before passing it to vim.system()
request client module should be refactored a bit to get this