dashboard/app: introduce authorized access to public resources

[tarasmadan]

1. This PR unit test the accessLevel function internals and
2. Introduces the authorized AccessPublic requests

We need AccessPublic authorization primarily to stop throttling our own service accounts.

[a-nogikh]

2. Introduces the authorized AccessPublic requests

We only need that to create the reproducers archive?

[tarasmadan]

We only need that to create the reproducers archive?

I need it for reproducers now.

[tarasmadan]

@a-nogikh let's #5412 first then.

[tarasmadan]

Let's add the full ACL then?
What we have now is AuthDomains []string
Let use the next one instead:

type ACL struct{
    Email   string
    Domain  string
    Access  AccessLevel
}

Email != "" || Domain != "".
We can later add the Namespaces []string.
If the requester is authorized by this list - disable throttling.
@a-nogikh deal?