Check for blocked repos in SSH RPC

[vlad-ivanov-name]

Change: I7f51aac51b166f0bd85ec51a934711be129558c8

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Stack:

• Refactor: move argument parsing out of josh-proxy.rs, define struct #1019
• Refactor: use a sum type instead of a bool to indicate need for auth #1016
• Check for blocked repos in SSH RPC #1015 ⬅
• Make auth optional in make_meta_config #1014
• Check if repo is blocked before checking auth #1013
• SSH support, part 1 #1012

⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.

[vlad-ivanov-name]

✓ Commit merged in pull request #1019