add role which updates nginx config for the blobs server

[chereseeriepa]

This adds configuration to the domains nginx config file so that requests are passed along to the blob server.

In our case, a request looks like this:

https://graphql.planetary.pub/blob/:blobId

And is the converted to this for the blob server to handle:

http://127.0.0.1:26835/get/:blobId

Notes:

• I made the location /blob as it was a lot tidier than https://graphql.planetary.pub:26835/get/:blobId