Show compatibility flag when starting the server

[manniL]

Describe the feature

In addition to the Nuxt and Nitro version, the compatibility flags could be shown in the terminal when starting the Nuxt dev server, so people using the "future" flags are sure they work as expected.

Additional information

• Would you be willing to help implement this feature?
• Could this feature be implemented as a module?

Final checks

• Read the contribution guide.
• Check existing discussions and issues.