[Cashtab][Pt1/2] Parse Airdrops in TxHistory

Summary: Related to T2415. Sent and Received airdrops now show the airdrop icon, along with the token icon. Pt 2 will add the token name from cashtabCache.

Test Plan:
cd web/cashtab && npm start
if there are no sent and received airdrop txs in recent tx history, make them
observe that the Airdrop Icon shows for airdrop txs
observe that the eToken Icon shows for the related tx

Reviewers: bytesofman, #bitcoin_abc

Reviewed By: bytesofman, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D12195