feat: Ability to customise default environments for new project

[khvn26]

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Changes

This PR adds the default_environment_names_for_new_project FoF flag to customise default environment names when creating a new project.

How did you test this code?

Ran the build locally.

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[matthewelwell]

What was the reason for making this a flag vs an environment variable?

[novakzaballa]

The code looks good, but for some reason, several tests failed at the same place: AssertionError: waitForElementVisible([data-test="features-page"])

[novakzaballa]

I ran the e2e tests locally, and they failed.

[github-actions]

Uffizzi Preview deployment-50361 was deleted.

[khvn26]

What was the reason for making this a flag vs an environment variable?

@matthewelwell I figured this setting is analogous to etc. segment_operators.

TBH I'd move all settings to FoF if it was up to me, leveraging the offline mode for static/default values.

[khvn26]

@novakzaballa Found the error and fixed it!

[novakzaballa]

Looks good, but I couldn't find the new flag default_environment_names_for_new_project in prod.

[khvn26]

@novakzaballa The default value will be used for SaaS. The flag is intended for private/self-hosted installations.