Clear and concise description of the problem

Instead of setting describe.concurrent, it'd be great to have an option to set it as a default.

Suggested solution

Add config option --concurrent

Additional context

Currently, if a project wants to enforce use of concurrent for all tests, it's practically impossible to do so, because:

• vitest doesn't have a config option to set it globally
• if a project adds a wrapper and asks developers to use this wrapper everywhere, there could still be instances when a developer would forget to do so by importing a describe from vitest or use a globally provided describe
• there is no such ESLint rule in eslint-plugin-vitest

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.