[Cashtab] Use in-node chronik to calculate airdrops

Summary:
Use in-node chronik to calculate airdrop txs instead of SLPDB

This dramatically increases the speed of airdrop calculations. What used to take 30s to 90s, depending on the token history, is now instantaneous or within 10s.

Large diff, but

• All new functions are unit tested
• Integration tests are added to Airdrop.js confirming expected behavior

Various knock-on impacts of this diff

• mock-chronik-client had to be updated to properly mock the features used (new tokenId endpoint)
• lots of etoken: address conversion functions no longer necessary (these worked with the format returned by etoken-list)
• etoken-list is no longer used and can be deprecated
• tokendb.kingbch.com is officially obsolete and will be shut down
• we do not need a progress bar for the airdrop calculation. This will almost always be "instant," and only takes some time for tokens with a large amount of holders. we continue to lock the UI and show a spinner while Cashtab is calculating an airdrop.

Test Plan:
npm test

This diff is live at https://cashtab-local-dev.netlify.app/

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D15766