ENSRainbow: Handle command line arguments

[djstrong]

• Implement CLI apps for ingest, index and count-keys, move code to lib
• Allow setting log-level in index
• Add option to validate maybeLabelHash in ingest

index.ts
I'm not a fan of using NODE_ENV in this way because it's not explicit enough. We should be highly explicit in all our environment variables, including how they are documented in the README.

One option is to move this out of an environment variable and instead into a command line argument. Ex: How Ponder handles this goal with the --log-level environment variable. https://ponder.sh/docs/api-reference/ponder-cli

Suggest we not grow this PR any bigger though and that these ideas are moved into a separate issue for follow up in the future.

For an example of how we can setup ENSRainbow to handle various command line arguments, please see the strategy that Matt used in both of the tool apps here: https://github.com/namehash/ens-subgraph-transition-tools/tree/main/tools

Originally posted by @lightwalker-eth in #133 (comment)

ingest.ts
It would also be nice to have a mode where we validate that maybeLabelHash is equal to labelhash(labelHash). In other words, to validate that the key -> value relationship is actually correct. It's good to challenge and validate assumptions.

#133 (comment)