Reorganise the metrics

[aurelticot]

Suggested structure:

/
|
|__ /identities
|   |
|   |__ /polyamoy
|   |   |__ stats.csv
|   |
|   |__ /polpos
|       |__ stats.csv
|
|__ /networks
    |
    |__ /banksia
    |   |__ nodes.json  # List of all the nodes with their metadata (label, endpoint, ...)
    |   |__ stats.csv   # Overall stats of the network (capacity, ... maybe other in the future)
    |   |
    |   |__ /[nodeId]
    |       |__ stats.csv  # Individual stats of the node (capacity, ... maybe other in the future)
    |
    |__ /myrtle
        |__ nodes.json
        |__ stats.csv
        |
        |__ /[nodeId]
            |__ stats.csv

Basically:

• The current /nodes/[network]-nodes-summary.json would become /networks/[network]/nodes.json
• A new /networks/[network]/stats.csv would be holding overall network stats as needed for Compute the overall network capacity and expose these metrics #9
• All the individual node stats would move from nodes/[nodeEnpoint]/stats.csv to /networks/[network]/[nodeId]/stats.csv