PoW Faucet

[harryttd]

Tezos faucet chart updates for the new PoW challenge functionality.

See https://github.com/oxheadalpha/tezos-faucet-backend/pull/2 and https://github.com/oxheadalpha/tezos-faucet/pull/16

Notable changes:

• Can configure separate RPC url for the backend code. This way the backend can query the k8s node rpc service directly.
• Deploying the frontend is now optional, so you can have just a programmatic faucet.
• Added pod security context, service account, plus other Helm k8s configuration options.
• Removed unused secret.
• General cleanup and improvement.