Support filter-pool argument

[wolf31o2]

Let's support a filter-pool argument which should filter to:

• Blocks issued by the pool
• Delegation transactions to the pool
• Pool registration changes

[ccgarant]

This would be awesome especially for a screen and audio tracking a pool for blocks won, delegation, and maybe even big stake increases within the wallet, perhaps event pool certificate changes.

[wolf31o2]

Currently, blocks won, delegation (in), and pool changes can be tracked easily. For wallet, you would need to track the stake of every single wallet, which would also need rewards calculations. We're not quite there, yet.

[wolf31o2]

Blocks: #112
Delegation: #209
Registration: #210