[dashboard] Handle EE_LICENSE_REQUIRED

[AlexTugarev]

For Gitpod Self-Hosted installations the server component may return EE_LICENSE_REQUIRED error responses.

We need to implement a catch for these errors and also the page where to upload the EE license on.

[AlexTugarev]

@gtsiolis, this one would need to be redesigned 🙏🏻

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[mrsimonemms]

I think this ticket is actually quite a good change and will be the first way of self-hosted users entering the sales funnel. Since #8593, this will only be triggered by people who are not paying for Gitpod and have 11+ users. The alert should now be "this feature is disabled in the community edition - why not upgrade your Gitpod installation" and then direct them to the page to allow them to upgrade to a paid license.

This payment gateway/license generator will be covered by #8717

/cc @gitpod-io/engineering-self-hosted @gitpod-io/engineering-webapp

[lucasvaltl]

Closing this because what is in this ticket is super-seeded by #9971 and the other tickets linked above.