Optionally force default locale url prefix

[11koukou]

Describe the feature you'd like to request

As per the #18419 discussion I would like to open a feature request just in case that the mentioned post is no longer being monitored due to having being "answered".

Well, it is a much requested feature to optionally force the locale appear in the url even if it is the default one. The current middleware workaround is more or less what its name exactly means: a workaround. It introduces unnecessary complexity and even drops performance, for something that is hypothetically simple.

Describe the solution you'd like

Having a "forceDefaultLocalePrefix" boolean flag in next.config.js

Describe alternatives you've considered

None