[Cashtab] Remove classNames from Tx.js

Summary: Related to T2592. Removed unnecessary classNames from Tx.js and replaced them with styled components. One className, antd-collapse, has been removed without futher changes as it was not being used in the Tx component.

Test Plan:
cd web/cashtab && npm start
Ensure there is at least one sent, one received and one genesis tx in TxHistory.
Observe that the styling for sent, received and genesis is maintained.

Reviewers: bytesofman, #bitcoin_abc

Reviewed By: bytesofman, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D11826