RC2 for Prater

This is Release Candidate 2 of the Smartnode stack, which is targeting the testnet on Prater.

New CLI Functions

• rocketpool node claim-rpl: lets you manually claim RPL rewards after a checkpoint.
• The new --nonce global flag can be used to manually set the nonce of a transaction, which can be useful for overwriting an existing "stuck" transaction with a gas price that's too low.

Config Updates

• Added support for the Pocket Network as a decentralized ETH1 light client option.
• Added the rplClaimGasThreshold setting, which lets you set a gas price limit on automatic RPL reward claims - if the network price is above this limit, automatic claims will not go through. Setting it to 0 will disable auto-claims entirely.

Misc Updates

• Changed the smartnode and smartnode-pow-proxy Docker images to use Alpine instead of Ubuntu as a base. This greatly lowers their size, and offers a better security footprint since Alpine provides a smaller set of capabilities for attackers to use.
• Added support for an improved total effective network stake calculation to make RPL rewards more accurate.
• Fixed timezone validation during node registration.