Add x-node-url response header to requests

[zomglings]

Changes

The x-node-url response header specifies which node a JSONRPC request served by a blockchain (not database) was served from.

How to test these changes?

Tested locally with curl:

curl -v --request POST "http://127.0.0.1:8544/nb/polygon/jsonrpc?access_id=$NB_CONTROLLER_ACCESS_ID&data_source=blockchain" \
    --header 'Content-Type: application/json' \
    --data-raw '{
        "jsonrpc":"2.0",
        "method":"eth_blockNumber",
        "id":1
    }'

Related issues

[zomglings]

@bugout-dev check

• Depends on Supports tags filter for nodes #741

[zomglings]

I don't want to merge this. I would like to add a name field for nodes and then use the name in a response header instead of hte full JSONRPC URL. The current implementation could leak access keys to third party node providers.