get rid of 1 of 3 provider.json's

currently we have provider.json in use in 3 different locations e.g. riseup.net/provider.json, black.riseup.net/provider.json and api.black.riseup.net:443/provider.json.

We should only keep black.riseup.net/provider.json and api.black.riseup.net:443/provider.json, whereever we depend on riseup.net/provider.json we should use black.riseup.net/provider.json instead.

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