[CLI Feature] Client status, show transaction rate and pool stats

It would be motivating to see the transactions per second (perhaps over a 24 hour sliding window) for the entire network.

It would also useful to see the number of transactions pending in the pool.

coda client status

Coda Daemon Status 
-----------------------------------

Global Number of Accounts:                     18
The Total Number of Blocks in the Blockchain:  1
Local Uptime:                                  36s
...
Transactions per second (24hr):                3.14
Pool size:                                     271
...

This would be helpful for monitoring and debugging to see what’s the current “demand” and whether the network is keeping up.

discord: jspadave